The strangest possibility: The physical world may be exactly what it seems to be

Is the physical world really made of abstract, mathematically-defined atoms?

Mystery has to do with deeper truths hiding behind mere appearances. What we see and hear is just appearance; the physical world, as it is in itself, consists of unexpected and mind-boggling truths—or so we imagine. Yet, perhaps the greatest of all mysteries is hiding in plain sight, right under our noses. Indeed, if we ponder our situation carefully, we come to the startling realization that the strangest possibility of all is this: the physical world may be exactly what it seems to be. This possibility, if true, would force us to part with our dearest narratives about the nature of reality.

According to the mainstream story, the physical world consists of particles and force fields defined in purely mathematical terms. These particles and force fields have only abstract, quantitative properties such as mass, charge, momentum, position in spacetime, spin, etc. But they entirely lack intrinsic qualities: the physical world out there, in and of itself, has no smell, tone, taste, color or texture. Instead, these qualities are supposedly generated by our brain, inside our skull. The red you see exists solely inside your head; out there there are only electromagnetic fields with a certain—quantifiable—frequency of vibration. The texture you feel exists only inside your head; out there there are only geometric arrangements of molecules. That we attribute color and texture to things out there is merely a projection, a psychological artifact of our cognitive apparatus. All the qualities you perceive around you right now are—or so the story goes—inside your head. Your real skull is beyond everything you perceive, encapsulating your whole experiential world like an invisible eggshell beyond the horizon. This—absurd as it may sound when rendered explicit—is what is supposed to be going on.

What motivates such a counterintuitive story? The main reason is that we all seem to inhabit the same world. If you were sitting next to me right now, we would both describe my living room in a mutually consistent manner. Yet my perception of the room would be different from yours in the details, given our slightly different perspectives within it. There thus appears to be a non-mental environment outside our respective perceptual fields, which is occupied by both of us and modulates our experience of the room. This environment is supposedly the physical world out there.

There are other reasons. For instance, although we can change the world of our imagination by a direct act of volition—I can imagine a pink elephant in my living room right now, if I wish… Oops, just did it—the same is not the case when it comes to the physical world. Unlike the images in our mind, the physical world has an autonomy that seems to place it outside our mind. Ergo, it must have no qualities, for the latter are essentially mental. Moreover, there are undeniable correlations between our inner experiences and measurable patterns of neural activity in our brain. This suggests to some that these experiences are somehow—nobody understands how, not even in principle—generated by our brain.

But the question is: Is there an alternative narrative that honors our intuition that the physical world—concrete physicality itself, as we normally understand it—consists of qualities of experience, such as color and texture? That what is physical is the touch I feel in my hands, the smell I feel in my nose and the taste I feel in my tongue, as opposed to abstract mathematical relationships? Can this narrative also make sense of the facts that we all seem to inhabit the same environment, that we can’t change it through a direct act of volition, and that patterns of brain activity do accompany experience? The answer is yes, as I have extensively and painstakingly elaborated in my book, The Idea of the World.

Available on amazon.

In such a short essay, it is impossible to go into the argument in any depth. But in very general terms, the story goes like this: the physical world is exactly what it seems to be, in the sense that it consists solely of the concrete qualities we experience as physicality—namely, the colors we see, the smells we feel, etc. Therefore, the physical world exists entirely within our mind… But not within our head! Our body is itself part of the physical world, so it is our body that is in our mind, not the other way around.

Does this mean that all reality is our private dream? That would follow only if the physical world were all there is. But we know that, in addition to the qualities of perception—that is, color, taste, smell, etc.—there are other mental categories, such as thoughts and feelings. So even if all perceptions are fundamentally private, we may still be immersed in a shared environment constituted by transpersonal thoughts and feelings.

In other words, the physical world is private, all right, but there is still a non-physical world of transpersonal thoughts and feelings—to which we have no direct access—surrounding us and which we all inhabit. What we experience as our perceptions of the world ‘out there’ is merely the outer appearance of these transpersonal thoughts and feelings; just as our brain and its neural activity is the outer appearance of our own private experiences. The whole physical universe is akin to a brain scan image of the mental activity of a mind at large, in which we are immersed.

So there is indeed a great mystery behind the appearances: What are these transpersonal thoughts and feelings that present themselves to us as the physical world? Although the latter is nothing more than our perceptual experiences—which we merely describe by means of abstract mathematical relationships—it points to something non-physical, ineffable, concurrently immanent and transcendent. While being exactly what it seems to be, the physical world still hints at something beyond itself. Therein lies the mystery.

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Why dismissing philosophy threatens the integrity of science

Bust of Aristotle, second century AD.
Photo by Bernardo Kastrup, hereby released into the public domain.

It has become sadly common for science popularizers to dismiss philosophy as an empty, altogether useless discipline consisting of circular abstractions. Even scientist Stephen Hawking went as far as to declare philosophy dead. I believe this public dismissal of philosophy, rather than reaffirm science, brings harm to its integrity.

To substantiate this claim, I must first discuss the differences between science and philosophy. Of the many areas of philosophical investigation, two are particularly relevant to science: ontology—that is, the study of what things are in and of themselves—and epistemology—that is, the study of what we can know about them and how we can know it.

The scientific method rests fundamentally on empirical observation: we can theorize all we want, but it is by comparing our theories with observations of nature that we can confirm, discard or refine these theories. However, from an epistemic perspective, all we can know from observing nature is its appearance and behavior. Let me unpack this.

Observation, by definition, only gives us access to how things appear to us—through the mediation of measurement instrumentation, as the case may be—not to what they are in themselves, independently of observation. For instance, when you observe another person, her facial expressions may often seem to betray a range of emotions you’ve had before. But you cannot access her emotions in and of themselves, as she feels them, independently of your observation (unless, of course, you become the person).

Because it is fundamentally based on how nature presents itself to our observation, the scientific method provides no direct insight into what things are in themselves. Indeed, assuming that a thing’s appearance directly implies what it is in itself overlooks a host of possibilities and questions, as I shall discuss shortly.

Even when we use giant particle accelerators to smash matter down to its most basic building blocks, all we can access is how the resulting debris appear to us via our measurement instruments. Since we cannot become a quark, a lepton or a boson, the universe as it is in itself—insofar as it is constituted by quarks, leptons and bosons—remains fundamentally inaccessible through scientific investigation.

More specifically, science concerns itself exclusively with the behavior of nature as presented to observation. Scientific theories are predictive: given a sufficient characterization of a system, a good theory anticipates what the system will do next. For instance, if I know the relevant characteristics of a billiard table, balls and cue stick, I can predict what will happen after I strike the cue ball. But predicting what will happen is a foretelling of the system’s behavior, not a direct insight into what the system is.

Available on amazon.

Doing science consists in systematically observing and modeling the patterns and regularities of nature’s behavior, so it can next be predicted. It is this ability to predict how nature will behave that enables the development of technology: if one puts some materials together in a certain way, a certain useful effect can be reliably expected to follow.

Indeed, the key carriers of the value of science for our civilization—and perhaps the key reasons it has accumulated so much cultural currency—are the technologies that address pressing human needs and desires. Analogously to how one can play and win video games without any understanding of the underlying hardware or software, these technologies can be made to work even without insight into what nature is in itself.

But for there to be natural behavior as revealed through appearance, there has to be something that behaves and appears to begin with. In other words, there has to be nature-in-itself. The problem is that comparing behavioral predictions to empirical observations cannot reveal nature as it is in itself, for many different hypotheses regarding the latter are consistent with the same behaviors.

This is why crucial questions cannot be answered by science alone, such as: Are the fundamental subatomic particles merely abstract entities whose nature can be exhaustively characterized in purely quantitative terms? Or do they have intrinsic qualities, such as color, flavor and smell? Are the fundamental subatomic particles the external appearance of conscious inner life at a microscopic level, analogously to how your brain is the external appearance of your conscious inner life? Is all matter in the inanimate universe the external appearance of universal conscious inner life? Or are both matter and consciousness different aspects of a third, more fundamental category, which appears as matter or consciousness depending on perspective? No method of acquiring knowledge based on behavioral appearances can, on its own, tackle such questions of being.

That science gives us insight only into appearance and behavior is the conclusion of an epistemic analysis: an eminently skeptical, meta-cognitive critique of what can actually be known, so we don’t inadvertently take mere belief for knowledge. An attempt to investigate what nature is—as opposed to how it behaves—requires, in turn, the philosophical method of ontology, which is based on principles of internal logical consistency, empirical adequacy and categorical parsimony. This is how philosophy complements science, attempting to address issues that fall—fundamentally—beyond the scope of scientific investigation.

When science popularizers dismiss philosophy, they are making one or more of several mistakes, amongst which: (a) being unaware and uncritical of the intrinsic boundaries of their preferred method of knowledge acquisition; (b) taking one particular ontology—usually, mainstream physicalism—for the self-evident truth, thereby projecting an unexamined belief system onto nature; (c) extending the scope of science beyond what is justifiable by its method, thereby putting the integrity of science itself at risk. All these are errors that can easily be avoided with a minimum investment in self-education.

Just as science needs philosophy to address more fundamental questions about the nature of being and the boundaries of knowledge, philosophy also needs science: any viable ontology needs to be informed by, and accommodate, the patterns and regularities of nature’s behavior discerned through the scientific method. Any theory about the world-in-itself that contradicts—by implication—these observed patterns and regularities isn’t empirically adequate and, therefore, must be discarded.

There is thus a crucial bridge between science and philosophy. On one side of this bridge, there is a method based on observation, modeling and prediction of behavior; on the other side, a method based on explicit, clear, meta-cognitively-informed reasoning. The bridge allows for productive commerce between the two, which—when suitably leveraged—can lead to remarkable conclusions about the nature of reality, such as those discussed in my new book The Idea of the World and very briefly described in the video above. However, negating this bridge and attempting to tackle all questions with one method alone can only overextend and rob this method of its integrity.

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Nothing short of pathetic: The Skeptical Inquirer's "review" of my ideas

Sometimes it's difficult to know whether to laugh or yawn.

It has been brought to my attention that the Skeptical Inquirer magazine is publishing a "research review" of my ideas in its January/February 2019 issue, which is already available. I did a search online to learn more about this magazine and, according to Wikipedia, recognizable figures such as Isaac Asimov, Martin Gardner, Carl Sagan, Francis Crick, Neil deGrasse Tyson, Lawrence Krauss, Richard Dawkins, Bill Nye, Daniel Dennett and Steven Weinberg are counted amongst its past and present fellows.

It's hardly a secret that I am highly critical of some of the figures above, but I have much respect for some of the others too. So I assumed that the "review" would at least provide a thoughtful look at my work and offer substantive criticisms I haven't faced or addressed before. I thus decided to pay the required fee and download it. What I then saw made me concerned not for my work, but for the good name of science itself. Allow me to elaborate on this apparently exaggerated claim.

The "review" focuses solely on a Scientific American essay I wrote with two psychologists, which offers a very brief summary of how psychological dissociation could provide a solution to the so-called 'decomposition problem' in philosophy. It is a brief overview of a much more extensive academic paper published in a leading journal.

It's abundantly clear from the Skeptical Inquirer "review" that its author did not read the academic paper. The main problem, however, is that he didn't properly read even the short Scientific American essay itself. For instance, he claims that "it wasn't long before quantum physics [was] tossed in." Our essay, however, doesn't touch on quantum physics at all; the word 'quantum' never even appears in it. The Skeptical Inquirer author seems to have entirely hallucinated it out of thin air. He also seems to assume that we were endorsing panpsychism, while our essay is in fact highly critical of it.

He proceeds to criticize a third-party academic paper on Multiple Personality Disorder (MPD), published in a highly respected journal, which we cited in our Scientific American piece. The criticism, however, centers on a basic issue of experimental design that is certain to have been considered during the peer review process. Going further, the author then criticizes another third-party study we cited: one in which researchers realized that, when a blind dissociated personality was in control of an MPD patient's body, the visual cortex activity normally associated with vision would disappear, even though the patient's eyes were wide open. The author tries to dismiss the "patient's subjective claims of blindness" as mere "functional blindness" or "conversion syndrome," both of which are psychological conditions of a subjective nature, related to suggestibility, stress and inner conflict. He seems to have somehow entirely missed the one point of our claim: that objective EEG measurements were performed, which failed to detect visual cortex activity when a blind personality was in control, even though the patient's eyes were open. These same EEG measurements then detected the appropriate visual cortex activity the moment a sighted personality assumed control. Somehow the significance of this result seems to have completely flown over the author's head, even though it's rather obvious to any mildly attentive and educated reader, this being the reason why the result received significant media attention (see e.g. this extensive Washington Post report).

Clearly, what the author thinks we claim in our essay—and now I have to stop myself from laughing as I write these words—is that one has to have MPD in order to understand life, the universe and everything! No, really, this is nothing short of hilarious. Not even an average high-school student would have misunderstood our point so pitifully.

Be that as it may, most of the "review" is dedicated not to attacking the original ideas discussed in our essay, but third-party, peer-reviewed research on MPD instead. This may have to do with the fact that the author is some retired psychiatrist from Iowa, but the dissonance between claim and substance is striking. As a matter of fact, the author never actually even says what our original ideas are, or how they relate to MPD! Dedicating a single sentence to it was apparently considered unnecessary in an article that claims to review my philosophy.

Interestingly, the author does find it worthwhile to dedicate a significant part of his "review" to emphasizing that MPD patients suffer severely from forms of cognitive impairment and emotional distress. This, according to him, "contradicts the foolish notion that MPD would ever help anyone make sense of life, the universe, and everything" (the title of our Scientific American essay is "Could Multiple Personality Disorder Explain Life, the Universe and Everything?"). Clearly, what the author thinks we claim in our essay—and now I have to stop myself from laughing as I write these words—is that one has to have MPD in order to understand life, the universe and everything! No, really, this is nothing short of hilarious. Not even an average high-school student would have misunderstood our point so pitifully.

To his credit, the author himself confesses to not having understood our Scientific American essay: he writes that "several paragraphs ... could only be described as incomprehensible" (for such a short essay, several paragraphs means that he didn't understand perhaps most of it). I can only point out that, if something is incomprehensible to him, it doesn't necessarily make it incomprehensible to the rest of us, attentive and educated readers. (On a side note, what kind of psychological disposition makes one feel entitled to publicly criticize something one has admittedly not understood?)

If the author is reading this post, let me take the opportunity to help him out a bit: Sir, the point of the title of our essay is that MPD, as an observable psychiatric condition, provides hints to something in nature that could help one address the so-called decomposition problem in philosophy. A philosopher who studies MPD is thus in a better position to solve the decomposition problem, without necessarily having to suffer from MPD themselves. Clearer now? You're welcome.

How can a magazine with ambitions to "promote scientific inquiry, critical investigation, and the use of reason" publish this kind of juvenile garbage? Where were the editorial controls? This "review" does no harm to me, but to the magazine, its readers and science in general (more on this below).

Here is someone who obviously has no clue of what he is talking about, and yet talks about it proudly. What a peculiar spectacle; what a dramatic illustration of the Dunning-Kruger effect.

What makes the profound ignorance betrayed by the "review" even worse is the conceitedness and pretentiousness that oozes through it. The cognitive dissonance between the two makes the "review" come across as somehow both hilarious and sad; maybe 'pathetic' is the right word. The conceited tone seems to be an attempt to 'play to the crowd,' appeal to some kind of mob mentality by throwing bones to what the author seems to assume are his readers' gullible prejudices. He talks of an "illogical leap into New Age Philosophy" when we argue that MPD can be literally blinding, even though we substantiate our claim with peer-reviewed research. He talks of 'consciousness,' 'panpsychism,' 'cosmopsychism' and 'idealism' as if these terms referred to woo (I am sincerely curious about what goes on in the conscious mind of someone who thinks that 'consciousness' is woo), instead of ontologies discussed in some of the world's most respected academic journals. Here is someone who obviously has no clue of what he is talking about, and yet talks about it proudly. What a peculiar spectacle; what a dramatic illustration of the Dunning-Kruger effect.

If I were a subscriber to the Skeptical Inquirer, I would feel offended by this "review." I'd feel that it treats me as someone who has surrendered their personal capacity for critical thinking to mob mentality. I'd feel that it treats me as a gullible participant of a political rally, eager to blindly cheer to shouted slogans, as opposed to someone who expects substantial and informed analyses.

Needless to say, the "review" reflects very poorly on both its author and the magazine that published it. And yet, one might point out that there are countless other examples out there of people proudly—though cluelessly—displaying the limitations of their intellects for the world to see. So why make an issue of this one instance?

Well, if this were all there is to it, I wouldn't have bothered to publish this post. But here we have a magazine that publicly associates itself with some of the most recognizable figures in science. At the very least, these figures are allowing this to be done and, by implication, allowing the image of science itself to become associated with such publications. To me, this is a serious problem. If the public begins to associate science, reason and critical thinking with the kind of "review" I've commented on above, we risk blurring the crucial difference between science, reason and critical thinking on the one hand, and the lunatic ravings of the fringes of our culture on the other. Once that crucial boundary is blurred, we're lost as a civilization.

Available on amazon.

My ideas may be controversial from the perspective of the current cultural ethos, but they are carefully and exhaustively substantiated. I have published many academic papers in respected journals elaborating on every facet of them. And now, I am publishing a 312-page book painstakingly making my case from an academic perspective. Let this work be my reply to my "critics."

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Why the world is imagined: A summary

To mark the release of the Uniform Reprints of my first six books—a major consolidation of my work—I want to summarize below, in language accessible to anyone, the key points of the philosophy explicated in much more detail in those books. So here we go.

According to the mainstream materialist paradigm, the world out there is made of subatomic particles and force fields outside and independent of consciousness. This world allegedly has no intrinsic qualities—such as color, flavor, smell, etc.—consisting instead of purely abstract quantities and mathematical relationships. The qualities of experience, according to this view, are created inside our skull by our brain: living organisms capture abstract stimuli from the external world through their sense organs, and then their brains supposedly translate these stimuli into the experiences that constitute their entire lives.

The notion that all colors, flavors, smells, etc., exist only inside our heads—instead of in the world beyond our heads—is profoundly counterintuitive. The motivation for believing it is the need to make sense of at least two facts: (a) there are strong correlations between patterns of brain activity and inner experience, which seems to implicate the brain in creating experience; and (b) we all seem to share the same world, so if experience is created by our individual brains, there must be something out there that isn’t experiential in nature, but which nonetheless modulates the experiences of different people through their respective sense organs. This non-experiential ‘something’ out there—that is, subatomic particles and force fields—allegedly is the world we all share.

The problem is that an increasing array of evidence seems to contradict the notion that experience is somehow created by patterns of brain activity. If this notion were correct, one would expect richer experience to always correlate with increased metabolism in the neural correlates of experience. Yet, the opposite has been observed.

The Uniform Reprint Collection

Indeed, psychedelic trances, which represent unfathomable enrichment of experience, are accompanied only by reductions in brain metabolism. Similarly, it has been observed that the brain activity of experienced mediums is reduced during the process of psychography. Patients who have undergone brain damage due to surgery have also been observed to have richer feelings of self-transcendence after surgery. Pilots undergoing G-force-induced loss of consciousness also report “memorable dreams,” even though blood flow to their brains is reduced. Teenagers worldwide play a dangerous game of partial strangulation, because the reduction in blood flow to their head leads to rich experiences of euphoria and self-transcendence. The list goes on, but the point should be clear: there are many cases in which brain function impairment correlates with enriched awareness, which seems to contradict the mainstream materialist paradigm.

To resolve this dilemma, one simply needs a subtle shift in perspective, a different way of seeing what is going on. Consider, for instance, lightning: Do we say that lightning causes atmospheric electric discharge? Certainly not: lightning is simply what atmospheric electric discharge looks like. Similarly, flames don’t cause the associated combustion: they are simply what the combustion looks like. Finally, a whirlpool in a stream doesn’t cause water localization in the stream: it is simply what water localization looks like.

These images—lightning, flames, whirlpools—say something about the process they are an image of: for instance, we can deduce many things about combustion from the color and behavior of the associated flames. More generally speaking, we say that there are correlations between the process and its image, for the latter is a representation—incomplete, as the case may be—of the former.

Returning to the whirlpool example, notice also that there is nothing to a whirlpool but water. You can’t ‘lift a whirlpool out of the water,’ so to speak. Yet, the whirlpool is a concrete and identifiable phenomenon: one can delineate its boundaries, point at it and say: “There is a whirlpool!” Images of processes can, after all, be very concrete indeed.

I thus submit that the brain—in fact, the whole body—is merely the image of a process of localization in universal consciousness; a localization of experience that, from a first-person perspective, makes up our private inner lives. The body-brain system is like a whirlpool in the stream of universal experiences.

The brain doesn’t generate experience for the same reason that a whirlpool doesn’t generate water. Yet, brain activity correlates with inner experience—the localized contents of the whirlpool—because it is what the latter looks like from a second-person perspective, just as lightning is what atmospheric electric discharge looks like from the outside.

The brain isn’t the cause of experience for the same reason that lightning isn’t the cause of atmospheric electric discharge, or that flames aren’t the cause of combustion. Just as flames are but the image of the process of combustion, the body-brain system is but the image of localized experience in the stream of universal consciousness.

In the same way that there is nothing to a whirlpool but water, I submit that there is nothing to a living body but universal consciousness. Yet, just as one can delineate the boundaries of a whirlpool and say “there is a whirlpool,” one can delineate the boundaries of a living body and say: “There is a body!” This explains the felt concreteness of living organisms under the hypothesis that all there is to them is universal consciousness.

The above is but a teaser of a much more elaborate theory of reality that is discussed in the six books of the now-available Uniform Reprints. I invite interested readers to peruse these books if they find the teaser above intriguing.

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Introducing the Uniform Reprints: Updated philosophy brought together as a whole

My biggest publishing news of 2018 is now officially out: the Uniform Reprints of my first six books. But wait: you have seen the new covers already; they have been around for a couple of months. "So, what's new?" I hear you ask. Well, the changes go much deeper than mere covers! "But if so, why only now make a breaking news item of it?" This, and many other questions you may have, is what I intend to address in this post.

What are the Uniform Reprints?

The Uniform Reprints are in-depth revisions of my six earlier books. The arguments have been refined and sharpened, with some ambiguous segments corrected. They have also been made consistent with one another, so that the six titles now contribute coherently to the same overall philosophical system, without seeming contradictions. Particularly, the usage of terms has been harmonized across books. Even my very first book, Rationalist Spirituality, which uses a dualist metaphor throughout, has been made more explicitly consistent with my idealist views.

Since their original publications, I have engaged in a number of exchanges about the books and fielded answers to countless questions from readers. This has given me a treasure trove of insights about how best to frame and word my case so it is better understood and misinterpretations are avoided. I have leveraged these insights while revising the text of the Uniform Reprints, which should thus be considerably clearer and more compelling.

All in all, the books now reflect and capture my thought in a more accurate, balanced and self-consistent manner. The Uniform Reprints also make clearer which role each respective book plays in the context of my overall philosophical ideas, and how they build on one another. One could even regard them now as one extensive six-volume work elaborating on a single theme from different angles and perspectives.

Why don't you call them new editions?

Since so much has been revised and improved, why don't we call these new versions full-blown new editions? There are several reasons, the most important of which is this: my publisher and I did not want to inadvertently deceive readers into assuming that these new versions have new material (such as new chapters, references, etc.). For clarity, let me say this: The Uniform Reprints do not have new material. They are revised, improved, sharpened versions of the same arguments and hypotheses already covered in the original versions. Improved as they certainly are, they do not cover new ground.

In addition, I wanted to supplant the earlier versions with these new revisions, because they are simply better at doing what I originally intended to do. If the revisions were published as new editions, the original versions would have survived, since new editions are basically new books, with new ISBN numbers. As it is now, the Uniform Reprints supplant the earlier versions entirely.

Should I buy a new Uniform Reprint of a book I already have?

This depends on the book and your personal situation, of course. One book in particular has been significantly improved: Rationalist Spirituality, my very first title. I am much happier with its Uniform Reprint version, as it is more accurate, compelling, clear and consistent with my idealist views. If any one of the Uniform Reprints deserves to be re-purchased if you already have the earlier version, it is this one. Of all my books, this is now the one that offers the most accessible, easy path into my ideas, because of its use of a dualist metaphor (body and soul, psyche and matter, etc.) that nearly everybody is acquainted with and have an intuition for. The original version already attempted this, but the Uniform Reprint is more successful at establishing a clear bridge from dualism to idealism.

Two other books have also been significantly improved: Meaning in Absurdity and Brief Peeks Beyond. The revisions here are less structural than in Rationalist Spirituality, but extensive and important nonetheless. If your interest in those two titles is high, it may be worthwhile to re-read them in their Uniform Reprint versions.

My best-selling title, Why Materialism Is Baloney, has gotten several improvements and corrections of passages that were ambiguous or not accurate enough. Dreamed Up Reality and More Than Allegory, on the other hand, required only language and terminology adjustments for accuracy and consistency with other titles; nothing too significant. Only real enthusiasts with no financial constraints should consider re-purchasing these.

Are the books still true to the originals?

I believe each one of my books belongs to its own time and circumstances, contributing an indispensable piece of the overall jigsaw puzzle I've been attempting to put together in the body of my work. Although my thinking has moved on since I've written them, in the sense that my focus has shifted, the earlier books still capture angles and perspectives integral—even indispensable—to the overall story.

As such, it has not been my intention, with the Uniform Reprints, to turn the older titles into different books. They remain true to what they were; to their time and nexus in the development of my philosophy. If anything, I've attempted to improve on what they already tried to achieve, without in any way defacing them.

So why are you announcing it only now?

Because the Uniform Reprints aren't new editions, they do not have new ISBN numbers. This means that they are treated as the exact same book as the original, logistics-wise. For this reason, there was no way to know whether a buyer would get a Uniform Reprint or an original version when purchasing: neither I nor my publisher have control over the stocks of retailers, so we couldn't be sure whether all the original versions had already been flushed out. (Naturally, this applies only to the paperback editions, as the e-book files have already all been updated.)

Had I announced the Uniform Reprints earlier, the chances that you would have gotten an older paperback version when purchasing—leading to possible disappointment—would have been high. So I felt it wasn't responsible to do so. And although even now I cannot be absolutely sure that the retailers' paperback stocks have been refreshed, the chances are at least much reduced, as I've waited literally months now. This is why this announcement is coming only today. Nota bene: I still can't guarantee that you will get the new version if you go and purchase a paperback now (the e-books are safe), for I simply have no control of the retailers' stock levels. On the other hand, if I were to delay the announcement much longer, it would hardly be news-worthy anymore.

Is this really such big news?

At least from my own perspective it certainly is. In fact, if anything, I've been holding my enthusiasm back throughout this post! If I could I would be throwing virtual fireworks here. The Uniform Reprints represent a consolidation of the body of my work that few philosophers have the opportunity to achieve in their lifetime. However much one tries to fine-tune and wordsmith a manuscript, the post-publication repercussion and feedback always provide embarrassing insights into what could have been done better. Thanks to my publisher, Iff Books, I have now had the opportunity to actually leverage these insights and firm up the foundations of my philosophy in a manner that gives me great confidence. The Uniform Reprints constitute a solid edifice of ideas argued cogently, compellingly and mutually-consistently. They also anticipate and preempt a number of the criticisms that could be made against them. The result is, hopefully, quite robust.

I still have many more books in me (in fact, I have been working on two yet-unannounced new manuscripts that even my publisher knows nothing about yet; so please don't tell anyone). But seeing the Uniform Reprints come out already gives me a great sense of fulfillment. If I were to write no more books in my life, I'd already regard this set of six (and now seven, with The Idea of the World) as my legacy to the world of philosophy. I hope you derive as much value from reading them as I have from writing, and now revising, the books.

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GUEST ESSAY: Further Response to the Psychedelic Neuroimaging Researchers

By Prof. Edward F. Kelly

(This is a guest essay by Prof. Edward F. Kelly, University of Virginia School of Medicine, Department of Psychiatry and Neurobehavioral Sciences. It follows up on an earlier essay and disclosure.)

Bernardo has already provided a swift and trenchant response to the critique of our recent Scientific American blog on psychedelic neuroimaging by six leading figures in that rapidly bourgeoning area of research. Here I wish only to add a few further comments, focusing primarily on issues of particular interest or concern to me.

It is noteworthy first that the authors do very little to address directly the intriguing topic announced in their title – “What Psychedelic Research Can and Cannot Tell Us About Consciousness” – and devote most of their attention instead to the theme of their subtitle – “A recent Scientific American blog misconstrues and oversimplifies the research”.

Let me speak immediately to our allegedly oversimplifying “the details” of the studies we discussed. These studies are all enormously complex, and within the constraints of the Scientific American blog forum (strict word limits, technical discussions discouraged) there is no realistic possibility of getting into the details of any one of them, let alone the whole lot. The best we could hope to accomplish was to convey a faithful overall impression of what has been accomplished to date and to indicate where the research seems to us to be heading. I believe we succeeded in that, but our critics do not.

They go on to give two primary examples of how we supposedly misconstrued the available findings. One, which Bernardo has already dealt with at some length, concerns the observed sharp reductions by various agents of activity in brain networks associated with ordinary conscious awareness – in effect, the neural embodiment of the everyday self or ego. Amazingly to us, the researchers now want to back away from their own early findings of this sort, which as Bernardo shows again in his rejoinder are anything but subtle. The observed reductions, that is, are big effects, easily detected using conventional and straightforward analysis techniques. They satisfy what statisticians sometimes jokingly refer to as the IOT test (InterOcular Trauma – it socks you right between the eyes). Those results are certainly not going away.

Even relatively simple neuroimaging methods can easily distinguish between wakeful and drowsy states and other commonplace conditions, yet here we seem to be having difficulty finding anything in patterns of brain activity that is even remotely commensurate with the extraordinary phenomenology of psychedelic states.

Now consider by contrast their other example, which involves possible increases in other aspects of brain activity that they think might help us understand the extraordinary phenomenology of psychedelic states. They accuse us of misrepresenting the observed increases in multichannel MEG signal “diversity” produced by several agents as “small” effects. What really matters, they now declare, are the statistical significance and effect sizes (using Cohen’s d) of the observed increases. Those results, however, depend strongly upon the very large numbers of 2-second MEG data segments that enter into the analyses. The exact Ns are not explicitly stated, but given information provided elsewhere in the report they likely range from something like several hundred for the psilocybin data to several thousand for the ketamine data. These large numbers are what drive successful statistical discrimination of mean differences between drug and placebo conditions that in absolute magnitude are in fact appropriately described as “tiny” rather than merely “small”. Specifically, on a diversity scale of 0 to 100 they average on the order of .005 across all drug/placebo pairs, and occupy the interval between .98 and .99 (see Fig. 2 in Schartner et al., 2017). For several subjects the observed mean differences between drug and placebo conditions even go in the wrong direction.

Now, an enormous amount of unusually sophisticated computation went into the generation of these results, and to both Bernardo and me they seem puzzlingly meagre. After all, even relatively simple neuroimaging methods can easily distinguish between wakeful and drowsy states and other commonplace conditions, yet here we seem to be having difficulty finding anything in patterns of brain activity that is even remotely commensurate with the extraordinary phenomenology of psychedelic states. Our critics are not troubled by this; instead they go on to describe some of the relevant experiential properties and simply urge us to believe that they will all somehow, someday, be “accounted for” or “underpinned”, or “explained by” physical properties such as the “diversity” of the accompanying brain states.

Let me remark here parenthetically that I don’t think “diversity” in the sense of unpredictability or randomness in multichannel neuroelectric signals is by itself a very good candidate for such a property. To me the facile equation of brain signal diversity with experiential richness and complexity seems at best premature, and reminiscent of the many instances since publication of Shannon and Weaver’s original treatise on information theory in which cognitive scientists and neuroscientists have glibly conflated technical and everyday meanings of the word “information”.

Be that as it may, however, Bernardo and I can certainly agree with our critics that psychedelic neuroimaging research is at a very early stage in its development, and we certainly don’t profess to know how far it may ultimately get. Indeed, in the original blog we even offered a concrete suggestion of our own as to how to carry it further.

But our critics don’t know either, and here we arrive at the bottom-level disagreement. All of them are apparently conventional physicalists, and for persons of that persuasion it is simply axiomatic, a given, that everything in mind and consciousness must be manufactured by, or in some mysterious way identical to, neurophysiological events and processes in the brain. In our original blog we had provided indications that not only popular interpreters of psychedelic neuroimaging research but the researchers themselves were showing signs of bias in favor of this physicalist picture, and Bernardo has already demonstrated that this 6-person response to our blog amounts to more of the same.

Everything comes to a head in their final paragraph, where they now start by accusing us not merely of misrepresenting but of deliberately misrepresenting their findings in order to motivate an alternative non-physicalist view. That accusation is false and offensive. To set the record straight, Bernardo and I began our very different scientific careers as conventional physicalists ourselves, but we have long since changed our minds in light of arguments and evidence presented in voluminous detail in earlier publications. We approached psychedelic neuroimaging research as genuinely interested and admiring outside observers, viewing the subject through that independently justified lens, and we could not help noticing the evident tensions between physicalist expectations and the experimental results that had started coming in. As a scientist with long-time involvement in the field of psychical research, I also noticed that the most prominent reported physiological effect of psychedelics, the reduction or disruption of activity in networks that stabilize ordinary everyday consciousness, has parallels in recent neuroimaging research with advanced practitioners of various kinds of meditation, and that both of those situations could be viewed as steps on the way toward one of the main empirical challenges to physicalist neuroscience – namely, mystical-type near-death experiences (NDEs) occurring under extreme circumstances such as deep general anesthesia and/or cardiac arrest in which physiological conditions regarded by virtually all contemporary neuroscientists as necessary for consciousness have been abolished.

Our critics end by openly revealing themselves as guardians of the physicalist faith, intent upon defending it against potentially dangerous infidels. It seems to them that merely by entertaining any possibility of an alternative conceptual framework or worldview we are somehow putting at risk the legitimacy of the emerging neuroscience of consciousness. That in my opinion is patent nonsense. Their own efforts in psychedelic neuroimaging are certainly not at risk. Indeed, one of the most exciting developments in contemporary neuroscience is surely the rapid intensification of efforts to relate improved measures of brain activity to improved measures of the phenomenological character of associated states of consciousness, and psychedelic neuroimaging provides an ideal arena in which to pursue and deepen that inquiry precisely because of the extreme character of the states involved. Friendly criticism ought not be perceived as a threat. The research will certainly go on unabated, and all of us – we and our critics alike – are enthusiastically supportive of that. Let the empirical chips fall where they may.

Bernardo and I have evidently had no impact whatsoever on these six critics, at least not yet, but perhaps other readers will prove more open-minded.

Copyright © 2018 by Edward F. Kelly. Published with permission.

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Setting the record straight with Robin Carhart-Harris and Enzo Tagliazucchi

Clouds on the horizon shall not obscure the light of facts.
(Photo by Bernardo Kastrup, hereby released into the public domain.)

As many of you know, I have been recently embroiled in a public exchange with a number of neuroscientists involved in the study of psychedelics. The exchange is about what I believe to be misinterpretations and misrepresentations of their results, as Prof. Edward Kelly and I argued in an opinion piece on Scientific American. Two days ago, the researchers replied on that same forum. I have commented on and rebutted their reply in this blog.

Yesterday, one of the researchers—Enzo Tagliazucchi—engaged in a de facto Twitter debate with me. Those interested can go on Twitter to peruse the many threads of that conversation. Here, however, I want to focus on a particular point, which I feel forced to vigorously counter. You will soon understand why.

First, a little background: about four years ago, one of the researchers, Robin Carhart-Harris, was busy promoting the results of the then latest psychedelic study of his team. This included a piece he wrote for The Conversation and an interview he gave to the Washington Post, amongst a number of other media engagements. Upon comparing his media statements with the actual study in question, however, I realized that things didn't add up: what the study actually said did not—either directly or by implication—support what Carhart-Harris was telling to the media.

The issue here seemed to be a basic misunderstanding of the signal processing analysis carried out in the study. Carhart-Harris was conflating changes in BOLD—a proxy for brain activity—level with changes in BOLD variance. I even went on to explain this difference in a 2014 post in this blog. I emailed Carhart-Harris to try and clarify the situation. Carhart-Harris then added Tagliazucchi to the discussion and, in a 2014 email to me, Tagliazucchi confirmed that I was correct.

But in my Twitter exchange with Tagliazucchi, I was accused of having been the party who misunderstood the issue in the first place! Here are the relevant tweets:

brain activation does not correspond to oscillatory activity! please survey the literature on the roles of these oscillations, especially the alpha rhythm.
We had a long time ago the same discussion when you confused changes in BOLD activity levels with changes in BOLD variance

— Enzo Tagliazucchi (@ETagliazucchi) October 27, 2018

The initial accusation of my having misunderstood the relationship between oscillatory activity and brain activation did not bear out upon further debate, as you can see if you peruse the broader Twitter exchanges. The salient issue here, however, is the accusation that—precisely opposite to fact—I was the party that conflated BOLD level with BOLD variance: in actuality, I was the one who noticed Carhart-Harris' conflation of the two and sought the authors out via private email to alert them to it.

This is amazing! CARHART-HARRIS confused BOLD activity levels with BOLD variance, and I corrected him. You know it because you confirmed it to me by email. You and Robin asked me not to release those emails, which I've respected for over four years. But if needed we can clarify.

— Bernardo Kastrup (@BernardoKastrup) October 27, 2018

Carhart-Harris had asked, after the fact, that I not make our email exchange public. I have honored this request for about four years now. Yet, here is Tagliazucchi publicly claiming the opposite of what actually happened in those emails, portraying me as someone confused with the neuroscience in question and in need of redressing. This puts me in a very uncomfortable position.

He proceeded to double-down on his claim and dare me:

I recall a different story - me explaining that the mean activity of the signal does not inform on the variance and vice-versa. Same goes for “brain activity“ and “brain oscillations“. But feel free to dig into your inbox.

— Enzo Tagliazucchi (@ETagliazucchi) October 27, 2018

For clarity, I don't doubt that he was being honest in these tweets, in the sense that he truly recalls the story in a distorted manner. Admittedly, the actual story is somewhat surprising: a philosopher, with no formal background in neuroscience, suddenly emailing the authors of a neuroscience study to correct their interpretation of their own study? The opposite would be more expectable, of course. Nonetheless, facts are facts. So I accepted the challenge:

OK, can I make it all public? I can do it this weekend, no problem. Are you okay with it?

— Bernardo Kastrup (@BernardoKastrup) October 27, 2018

If you are going to start reproducing correspondence we had in the past, it would imply an effort on my part checking that there is no bias in what you chose to reproduce and frankly I don't have the time, but as long as you keep it honest, there is nothing to hide from my part

— Enzo Tagliazucchi (@ETagliazucchi) October 27, 2018

I will edit nothing. I will just do a verbatim dump. But it does disappoint me beyond measure that you can INVERT the story! I reached out to you and Robin to alert you that higher spectral power did NOT imply a higher-amplitude time-domain signal, since you discard phase info.

— Bernardo Kastrup (@BernardoKastrup) October 27, 2018

Let me be absolutely honest and clear: I had agreed to Carhart-Harris' after-the-fact request not to make the emails public. I stick to my word and the very idea of disclosing those emails gives me a wrenching feeling in my gut. I don't take this at all lightly. But put yourself in my position now:

1. One of the people involved in that email exchange is now publicly claiming—without maliciousness, as I believe the case to be, but nonetheless publicly—that what happened was the opposite of what actually did. This inversion of the truth publicly portrays me as the ignorant and confused party, instead of the party that found the misunderstanding and then informed the authors about it. I have the emails to prove it. Should I continue to sit on them while Tagliazucchi's incorrect tweet stays online for all to see?
2. These same people—Carhart-Harris and Tagliazucchi are both co-authors of the Scientific American reply attacking me and Prof. Kelly—are now publicly accusing me of misrepresenting their psychedelic studies. I have the emails to prove that Carhart-Harris himself has been—and continues to be, insofar as he has never amended his erroneous earlier statements, as I shall discuss below—the chief misrepresenter of the work. Should I continue to sit on them?
3. In my Twitter exchange with him, Tagliazucchi repeatedly accused me of being ignorant of the basics of neuroscience. Consider this tweet, for instance:
   

   It is not a point about “silly ad-hominems“ - I would respond even if there were. But it is very difficult to discuss with someone who needs to revisit Neuroscience 101. The mere fact that he identifies “alpha power“ with “brain activity“ makes it so hard to engage.

   — Enzo Tagliazucchi (@ETagliazucchi) October 27, 2018

   I address the false accusation that I "identify 'alpha power' with 'brain activity'" in other tweets of the exchange. But be that as it may, should I continue to sit on an email exchange that demonstrates that, although some 101 basics were indeed misunderstood, it was not me who misunderstood them?
4. Tagliazucchi, one of the people involved in the original 2014 email exchange, has now given me public permission to disclose those emails. Should I continue to sit on them?

I feel Carhart-Harris and Tagliazucchi have left me no alternative but to defend myself and disclose the emails, for the reasons above. The record must be set straight. I can't remain silent in face of this onslaught.

(Post-publication clarification: In private correspondence after the original publication of this post, Tagliazucchi told me that his intent was to give me permission to publish only his own messages in the three-way exchange of 2014, not the messages he was commenting on. I acknowledge the clarification. But Tagliazucchi's messages alone would lack all context and much of the substance they refer to, thereby making it impossible for me to defend myself against his claims in point 1 above. Let it be clear, nonetheless, that I have four reasons to publish the 2014 exchange, only one of which is Tagliazucchi's permission. It has also been claimed, in private correspondence to me, that I am publishing messages originally shared with me in confidence. This, however, is not true. The messages were originally exchanged freely and openly, without any prior understanding regarding confidentiality, either explicit or implicit. I simply emailed Carhart-Harris asking for clarifications regarding public articles of his. There was no reason to think of confidentiality or for him to treat me any differently than any member of the public; he didn't know me back then. Only thereafter did Carhart-Harris ask me to not divulge the exchange. More specifically, this happened after he read the draft of an essay I sent to him, which was eventually published in my book Brief Peeks Beyond. In that draft, it was clear that my interest in Carhart-Harris' work was motivated by a metaphysical position I was trying to argue for. I shared the draft with him because I wanted to clarify in it, by reference to passages of our email exchange, that there was actually no finding of increased brain activity in the technical paper in question, despite how it was portrayed in the media. Carhart-Harris did not agree to it. My having not disclosed this material since then was a gesture of respect and courtesy towards Carhart-Harris and Tagliazucchi. But since Tagliazucchi, out of the blue and without prompting by me, now chose to refer to that original 2014 email exchange and characterize it as the opposite of what it actually was, the basis for that courtesy is nullified and I feel effectively forced to publish the exchange.)

Below, I reproduce the 2014 emails verbatim. I didn't correct even the typos, so I apologize if the text looks sloppy at times.

Here is my original email to Carhart-Harris, dated Monday, 17 November 2014, sent at 10:52am Central European Time:

Dear Robin,
I've been following your studies with psilocybin with interest since the preliminary publications in 2011. I've been reading mostly your technical publications but, today, read a popular science article you wrote here:
http://myscienceacademy.org/2014/07/05/magic-mushrooms-expand-your-mind-and-amplify-your-brains-dreaming-areas-heres-how/
In your 2012 PNAS paper you explicitly say that psilocybin decreases brain activity mostly in the DMN and doesn't increase it anywhere in the brain. In your new HBM study you talk of an increase in variability and spectral power of activity in dream-associated areas. Naturally, an increase in variability is not necessarily an increase in activity. Similarly, an increase in spectral density is also not necessarily an increase in activity, since phase information is ignored. I've concluded then that your new study in no way contradicts your earlier findings: psilocybin has NOT been found to increase sheer brain activity (metabolism, BOLD signal) in dream-associated areas, even though the media seems to have described the study that way. I've attributed the inaccuracy to journalists.
Yet, in your own myscienceacademy writeup you wrote "that psilocybin increased the amplitude (or “volume”) of activity in regions of the brain that are reliably activated during dream sleep and form part of the brain’s ancient emotion system." You also wrote of "the principle that the psychedelic state rests on disorganised activity in the ego system permitting disinhibited activity in the emotion system." Both statements are at least highly suggestive of a direct increase in brain activity ("amplitude," "volume," "reduced disinhibition"), even though no indication of this seems to be found in your technical papers (the HBM paper, for instances, talks of an increase in amplitude of variations).
I wonder if you could help me understand the discrepancy. Have you ever found that psilocybin increases sheer brain activity (BOLD signal, metabolism) anywhere in the brain?
Kind regards, Bernardo.

Carhart-Harris replied kindly and attentively on Tuesday, 18 November 2014, in an email I received at 12:12pm Central European Time:

Dear Bernardo,
Thanks for your email. The questions you raise are entirely valid and I would summarise it thus: the term 'activity' is generic and non-specific and not really that helpful or informative. With fMRI and FDG PET do not measure neural activity directly but instead via proxies, e.g. cerebral blood flow or glucose metabolism to index 'activity'. However, 'activity' used in this way is vague and we should probably not use it and instead just refer to the proxies. It is not certain for example that ASL fMRI and FDG PET measure the same 'activity'. My preference would be to move away from any reference to absolute increases or decreases in activity in relation to the action of psychedelic drugs. We get more information in the spontaneous oscillations and fluctuations in neural activity than we do in any absolute increases or drops in cerebral blood flow for example. If we observe increases in signal variance, this means the spontaneous signal fluctuations have a higher amplitude. You could interpret this as an increase in 'activity' but like I said, I'd prefer to avoid this and instead use a more specific term, i.e. an increase in signal variance or signal amplitude.
In short, we have mostly seen decreases in our measures of neural activity when looking at the brain effects of psychedelic drugs but it would be too simplistic to say all of these measures measure something that we can generically call 'activity' - as if it is something that is absolute, a quantitative thing that rises or falls. Instead, we need to think of these signals as dynamic and then think how best to describe the specific measures. My preference is to move towards referring to increases or decreases in the 'order' or 'organisation' of the systems from which the signal is recorded. I've attached an article that may help. When trying to communicate the results in the simplest terms, we often succumb to references to increases or decreases in activity but as I've said above, this isn't really the full picture and so, it can be misleading. It's a difficult trade off, knowing when to be specific but risk people not understanding what you're talking about or being generic but then over-simplifying the matter. If ever I make the 'mistake' of referring to increases or decreases in activity (which I do) then I need to hold my hands up and say yes, this is an over-simplification. You may find evidence of this over-simplification in what I have just sent you.
With best wishes,
Robin.

Kind as it is, this answer is evasive. It renders it virtually impossible to pin down what Carhart-Harris means whenever he uses the term 'activity.' How can it sometimes denote short-term fluctuations of metabolism and other times (such as in association with their 2012 PNAS paper) metabolism itself? Why use the term 'activity' repeatedly towards the media (e.g.: "psilocybin increased the amplitude (or “volume”) of activity in regions of the brain," and "You’re seeing these areas getting louder, and more active," etc.) if one means by it different things at different times? What are we to make of it, as readers? The need to simplify things towards the general public is acknowledged, but the simplification should still preserve internal consistency and comply to the standard meaning of terms used without further definition, lest the communications become at least misleading.

In any case, comparing brain activity levels between placebo and psychedelic conditions must somehow involve a time-averaged mean amplitude of the signal for each respective condition, not merely the signal's short-term fluctuations within a condition. But an analysis of variance says nothing about the signal's time-averaged mean amplitude. I therefore insisted on my point, in an email to Carhart-Harris and his supervisor, Prof. David Nutt, dated Tuesday, 18 November 2014, 1:10pm Central European Time:

Dear Robin and Prof. Nutt,
Thank you both for your prompt and thoughtful replies, which I much appreciate. Without meaning to abuse, I have a couple of very brief comments.

>> We get more information in the spontaneous oscillations and fluctuations in neural activity than we do in any absolute increases or drops in cerebral blood flow for example. <<

This is paradigmatically very significant and has profound implications as far as the biological basis of consciousness, as I am sure you realize.

>> If we observe increases in signal variance, this means the spontaneous signal fluctuations have a higher amplitude. You could interpret this as an increase in 'activity' <<

An increase in variance (and spectral power) can be tied to higher-frequency fluctuations, not only fluctuations of higher amplitude. An increase in variance can lead to signals of lower amplitude, if the frequency components are not in phase and thus interfere destructively. Isn't this correct? Assuming it is, I will be as bold as to disagree with you here. I acknowledge the ambiguity behind proxy measurements of activity, but activity itself is a clean concept tied to metabolism. Variations of levels of metabolism are not activity; metabolism is. Personally, I find it confusing to conflate these terms.

>> I'd prefer to avoid this and instead use a more specific term, i.e. an increase in signal variance or signal amplitude. <<

I concur. I have a brief question: in the HBM paper you report increases in the amplitude of fluctuations of the BOLD signal (i.e. amplitude of the delta in time). This leaves it unclear whether the amplitude of the BOLD signal itself, during bursts, was higher than in placebo controls. I could imagine that, even though time-averaged BOLD is not higher in the psychedelic state, brief bursts could be. Did you observe higher-amplitude bursts of the BOLD signal in the psychedelic state as compared to placebo controls?
On a more personal note, Robin, I enormously appreciate the work you and Prof. Nutt have been doing. You are pioneers in the full sense of the word. I am keenly aware of the pressures you are probably under, given the sensitivity of your work for our scientific and philosophical worldviews in general, way beyond neuroscience. Though I am critical of the ambiguity of your recent communications, I am very understanding of the potential motivations behind it, and tend to believe I would not have done better than you are doing.
Sincere regards,
Bernardo.

Carhart-Harris replied very openly and honestly in an email dated Tuesday, 18 November 2014, which I received at 2:09pm Central European Time:

Dear Bernado,
I've copied in Enzo, first author of the HBM paper to address your questions re signal variance. My understanding is that an increase in signal variance as it was measured in the HBM paper is equivalent to an increase in signal amplitude. Enzo may wish to comment on this.
As for reproducing my email response in print. If it's ok, I'd rather it not be. It was written somewhat in haste and I'd consider this more free communication rather than something sufficiently considered for publication. Perhaps if I could review and edit however, it could it principle be ok.
As for the issue re bursts. The increase in signal variance applies for a 5 min continuous period of scanning (post-infusion) and so is time-averaged. We did not specifically look at periodic bursts but this would be something interesting to look at. Would this be a Wavelet-like analysis Enzo? We'd need to know how to define a 'burst' in a systematic way. Since scanning was pure 'rest' there are no behavioural 'tags' to time lock 'bursts' to - but this is not to say they do not occur or that they are not behaviourally relevant. We'd have to be careful not to interpret motion artefact as a neurally generated burst. We have looked at 1 min time bins (see entropy analysis in HBM paper) Enzo is an expert on these more dynamic measures.
Best wishes,
Robin.

Carhart-Harris admits here that his "understanding is that an increase in signal variance as it was measured in the HBM paper is equivalent to an increase in signal amplitude." This is not true. Signal variance is equivalent only to the RMS (not peak) amplitude of the fluctuations of the signal; that is, what is left of the signal after one first subtracts the signal's mean value from it. Performing this subtraction, however, amounts to discarding the core information about the difference in time-averaged brain activity levels between placebo and psychedelic conditions, which can't then be compared. There seems to be, as such, a misunderstanding here on Carhart-Harris' part, which could explain the consistent media misreporting (e.g. this and this) claiming that the study in question found increases in activity in dream-related regions of the brain. The 'activity' reported to increase in these dream-related regions is, at any rate, something quite different from the activity proper reported to decrease in his 2012 PNAS paper. Under the normal denotation of 'activity' as a measure of metabolism, this 2014 paper showed no increases in activity—which, by the way, renders it consistent with the earlier 2012 results—despite Carhart-Harris' messages to the media.

Upon this email, Tagliazucchi, lead author of the study in question, replied on Tuesday, 18 November 2014, in an email I received at 2:57pm. In the email, he confirms my assessment:

Dear all,
Bernardo: indeed, variance is in this context just a measure of variability in the signal. Increased variance implies increased fluctuations of the signal, as opposed to a constant, unchanging signal. My interpretation of these fluctuations is that spontaneously occurring processes in the affected regions are engaging and disengaging more often under the psilocybin condition, so even if subjects are resting, spontaneous processes are more "active" and thus increase the variability of the signal. Following this line of thought, I'm interpreting signal variance as a sort of equivalent of BOLD signal amplitude but during rest (i.e. a measure of "something going on" you can apply during rest, as opposed to BOLD signal amplitude, for which you need a task paradigm).
Cheers,
Enzo

I find Tagliazucchi's "interpreting signal variance as a sort of equivalent of BOLD signal amplitude but during rest" misleading. Activity variability is not the same as activity proper; acceleration is not the same as speed. But never mind: the salient point in the context of this exchange is that Tagliazucchi recognized that my assessment was correct.

Misunderstandings do happen. I surely have misunderstood many things in my life and continue to do so. I don't think it can ever be avoided. My problem here is not Carhart-Harris' misunderstanding itself, but the false, inverted public portrayal of what happened in the 2014 email exchange. I also have a problem with something else: despite my explicit and repeated private and public requests for him to do so, as far as I know Carhart-Harris never rectified his mistaken media communications. As I write this, for instance, his original 2014 The Conversation essay remains unchanged.

Be that as it may, I hope this post sets the record straight once and for all.

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