Popper’s World 3

The Self and Its Brain: An Argument for Interactionism, a long exchange between philosopher Karl Popper and neuroscientist John Eccles, is among the most significant 20th century defenses of mind-body dualism. I do not agree with every aspect of their approach, but the book is filled with interesting things and deserves more attention than it has received in contemporary philosophy of mind.

Popper famously distinguished between three “worlds” or levels of reality. (Though whether “levels” of reality is the right gloss on Popper’s theory is not clear. “Kinds”? “Aspects”?) World 1 is the world of physical entities and states – tables, chairs, rocks, trees, fundamental particles and forces, human bodies and behavior, and so forth. World 2 is the world of thoughts, sensations, and mental phenomena in general. World 3 is the world of scientific and philosophical theories, arguments, stories, social institutions, works of art and the like. World 3 differs from World 1 in that the entities comprising it are abstract; for example, though a theory or argument might be embodied in a particular book (a World 1 object) it does not depend for its reality on the existence of that book, or on any book or World 1 object at all. We could still consider the Pythagorean theorem, know it to be true, prove it, etc. even if every geometry textbook that had ever existed were destroyed. World 3 differs from World 2 in being objective or public, whereas World 2 is subjective or private. Your thoughts and experiences are directly knowable only to you, but World 3 objects are equally accessible to everyone.

The objectivity or “autonomy” of such World 3 objects as theories and arguments is especially evident in Popper’s view from the fact that they have logical relations – and in particular, unforeseen implications and unnoticed inconsistencies – that may not be noticed until well after we first consider them, but which were evidently there all the time waiting to be discovered. Naturally, he takes mathematics to illustrate the point vividly, but it is in his view no less evident from empirical scientific theories. The clearest mark of the reality of all three worlds is in Popper’s judgment the fact that World 3 has a causal influence on World 1, and does so only via World 2. For example, the scientific theories which entailed the possibility of nuclear weapons have had an obvious impact on the material world – they have resulted in various nuclear tests, in the destruction of Hiroshima and Nagasaki, and so forth – but only because scientists carried out the mental activity of working out the implications of the theories and applying them.

Popper’s World 3 is often compared to Plato’s realm of the Forms, and Popper himself acknowledges that there are similarities. But he also emphasizes the significant differences between his view and Plato’s, not the least of which is that he takes World 3, despite its objectivity or autonomy, to be something “man-made,” its objects in the strict sense being what the human mind “abstracts” from their World 1 embodiment. Though Popper does not take note of the fact or develop the theme in much detail, this is clearly reminiscent of an Aristotelian or “moderate realist” approach to the traditional problem of universals, as distinct from the “extreme realism” of Platonism. (See here and here for a useful short account of the traditional Aristotelian-Thomistic-Scholastic approach to the issue and its significance.)

In other ways too Popper’s views as expressed in The Self and Its Brain overlap to some extent with Aristotelian ones. The emphasis on abstract thought – and thus on what is unique to human beings – as what is of greatest interest in the debate over dualism is very much in line with the classical Platonic-Aristotelian-Scholastic approach to this subject, which is quite different from the contemporary obsession with “qualia” and the like. There is also Popper’s acknowledgement of the reality of “downward causation” in physical systems and his consequent rejection of physicalistic reductionism even where non-mental phenomena are concerned. And there is his affirmation of the existence of objective “propensities” in nature, which (possibly) hints at something like the Aristotelian notion of potencies. (Though these last two themes take us beyond the World 3 thesis itself.)

On the other hand, there are some decidedly un-Aristotelian themes in Popper as well. There is, for instance, his denial of substance in favor of a “process” conception of the material world; and there is his rejection of essentialism, which he seems to assume is inherently Platonistic and committed to an a priori or “armchair” methodology. (This is a serious misunderstanding, and a very common one, which we Aristotelian-Thomistic (A-T) types find it rather tiresome constantly to have to rebut. See Oderberg’s Real Essentialism for the most thorough rebuttal, and pp. 30-38 for a reply to Popper specifically.)

All the same, any Aristotelian must admire the non-ideological character of Popper’s approach to the mind-body problem. Unlike so many contemporary philosophers of mind, he does not fatuously pretend that a presumption in favor of materialism has somehow been established by modern science, or that dualism rests on “intuitions” or the like. He does not present the problem situation as if it were a matter of determining whether we ought to wedge the evidence of our ordinary experience into the Procrustean bed of naturalism or instead to lop it off entirely – as if these were the only alternatives worth taking seriously. Nor does he have any theological ax to grind; he deliberately avoids getting into the question of the soul’s immortality (and even expresses the view that he would prefer not to be immortal). He merely observes that reality clearly comprises at least the three sorts of thing in question and that any serious solution to the mind-body problem will simply have to accommodate this plain fact. As The Self and Its Brain shows, Popper is also much better informed about the actual history of the mind-body problem than contemporary naturalists tend to be. (As my series of posts on Paul Churchland indicated, many naturalists seem unfamiliar with anything other than the crudest caricatures of what non-naturalist philosophers of mind have actually said.)

In short, at least where the mind-body problem is concerned, Popper does not attack straw men and he respects Butler’s famous dictum that “Everything is what it is, and not another thing.” (I put to one side for present purposes Popper’s views in political philosophy and philosophy of science, contexts in which he is more open to criticism on these grounds.) He thereby stands acquitted of a charge John Searle raised in The Rediscovery of the Mind against his fellow contemporary philosophers of mind:

[W]e let our research methods dictate the subject matter, rather than the converse. Like the drunk who loses his car keys in the dark bushes but looks for them under the streetlight, "because the light is better here,” we try to find out how humans might resemble our computational models rather than trying to figure out how the conscious human mind actually works…

[W]e ought to stop saying things that are obviously false. The serious acceptance of this maxim might revolutionize the study of the mind. (p. 247)

Like Searle, Popper is in my estimation better as a critic than as a positive theorist. (I discussed an important anti-materialist argument of his in an earlier post.) Still, from an A-T point of view even his positive theorizing is closer to the mark than that of most other contemporary dualists.

Augustine on the immateriality of the mind

In Book 10, Chapter 10 of On the Trinity, St. Augustine argues for the immateriality of the mind.  You can find an older translation of the work online, but I’ll quote the passages I want to discuss from the McKenna translation as edited by Gareth Matthews.  Here they are:

[E]very mind knows and is certain concerning itself.  For men have doubted whether the power to live, to remember, to understand, to will, to think, to know, and to judge is due to air, to fire, or to the brain, or to the blood, or to atoms… or whether the combining or the orderly arrangement of the flesh is capable of producing these effects; one has tried to maintain this opinion, another that opinion.

On the other hand who would doubt that he lives, remembers, understands, wills, thinks, knows, and judges?  For even if he doubts, he lives; if he doubts, he remembers why he doubts; if he doubts, he understands that he doubts; if he doubts, he wishes to be certain; if he doubts, he thinks; if he doubts, he knows that he does not know; if he doubts, he judges that he ought not to consent rashly.  Whoever then doubts about anything else ought never to doubt about all of these; for if they were not, he would be unable to doubt about anything at all…

Was Aquinas a materialist?

Denys Turner’s recent book Thomas Aquinas: A Portrait is beautifully written and consistently thought-provoking.  It is also a little mischievous, in a good-natured way.  A main theme of the book is what Turner characterizes as Aquinas’s “materialism.”  Turner is aware that Aquinas was not a materialist in the modern sense.  And as I have emphasized many times (such as at the beginning of the chapter on Aquinas’s philosophical psychology in Aquinas), you cannot understand Aquinas’s position unless you understand how badly suited the standard jargon in contemporary philosophy of mind is to describe that position.  Turner’s reference to Aquinas’s “materialism” is intended to emphasize the respects in which Aquinas’s position is deeply at odds with what many think of as essential to a “dualist” conception of human nature.  And he is right to emphasize that.  All the same, as I have argued before, if we are going to use modern terminology to characterize Aquinas’s view -- and in particular, if we want to make it clear where Aquinas stood on the issue that contemporary dualists and materialists themselves think is most crucially at stake in the debate between dualism and materialism -- then “dualist” is a more apt label than “materialist.”

Mind-body interaction: What’s the problem?

Aristotelian-Thomistic (A-T) philosophers often argue that an advantage of their view of human nature over that of the Cartesian dualist is that they don’t face an interaction problem.  Soul and body are on the A-T view related as formal and material cause of the human being.  Hence they don’t “interact” because they aren’t two substances in the first place, but rather two principles of the same one substance, viz. the human being.  Talk of them “interacting” is a kind of category mistake, like talk about the form of a triangle and the matter that makes up the triangle “interacting.”  So there is no problem of explaining how they interact.

Schrödinger, Democritus, and the paradox of materialism

Erwin Schrödinger was yet another of those early twentieth-century thinkers cognizant of the deeply problematic character of the mechanistic conception of the material world inherited from the early modern period – and yet another to see, in particular, that this conception of matter, far from opening the way to a materialistic solution of the mind-body problem, in fact created the problem and appears to make any materialistic solution to it impossible.

The reason does not (as one might suppose) have anything essentially to do with quantum mechanics, of which Schrödinger was one of the fathers. It has rather to do with a relatively simple philosophical point which was first made by the likes of Cudworth and Malebranche and repeated in recent years by writers like Nagel and Swinburne (as noted in the second of the earlier posts linked to above). Two relevant texts are Schrödinger’s essay “On the Peculiarity of the Scientific World-View” (from What is Life? and Other Scientific Essays) and chapter 6 of his Mind and Matter, entitled “The Mystery of the Sensual Qualities” (reprinted in What is Life? with Mind and Matter and Autobiographical Sketches – a more recent volume which does not include the earlier essay).

To summarize what I’ve said at greater length in earlier posts, the philosophical point in question is that the early moderns’ move of redefining matter so that it is devoid of color, odor, taste, sound, and the like as common sense understands them necessarily made these sensory qualities inexplicable in materialistic terms. Hence, if one is going to affirm the existence both of matter (as redefined by the moderns) and of the sensory qualities (or “qualia,” as they have come to be known, relocated from the external world to the internal world of the mind), then it seems one is necessarily committed to mind-body dualism of some sort (whether substance dualism or property dualism). The only way to avoid such dualism is either to reject the existence of matter (as Berkeley did), to reject the existence of the sensory qualities (as eliminativists do explicitly and most other materialists do implicitly), or to reject the mechanistic conception of matter that led to the problem in the first place (as Aristotelians do; though Aristotelianism still leads to a non-Cartesian form of dualism – what David Oderberg calls hylemorphic dualism – for reasons that have nothing to do with sensory qualities or qualia).

To be sure, Schrödinger himself does not explicitly draw an anti-materialist conclusion. He notes merely that what he calls the “objectivation” of matter – the conceptual removal from it of anything that smacks of the personal or of mind (cf. Thomas Nagel’s “objective/subjective” distinction) – makes the mind itself deeply mysterious. This is compatible with views like Colin McGinn’s “mysterianism” or Joseph Levine’s “explanatory gap” position, which affirm materialism even as they deny that we can understand, or at least (in Levine’s case) that we do in fact understand, how materialism can be true. Not that Schrödinger himself affirms this kind of view either; he simply calls attention to the problem raised by the modern conception of matter without trying to resolve it. (For my part, I consider McGinn’s and Levine’s positions non-starters. You might as well say, in response to Gödel, “Maybe the consistency of a formal system containing computable arithmetic really is internally provable after all, and our minds are just constitutionally incapable of seeing how.”)

Schrödinger’s emphasis is also less on the mind-body problem per se than on the epistemological paradox he sees implied by the modern “objectivation” of matter. As he puts it in “On the Peculiarity of the Scientific World-View”:

We are thus facing the following strange situation. While all building stones for the [modern scientific] world-picture are furnished by the senses qua organs of the mind, while the world picture itself is and remains for everyone a construct of his mind and apart from it has no demonstrable existence, the mind itself remains a stranger in this picture, it has no place in it, it can nowhere be found in it. (p. 216)

That is to say, the picture modern science (as informed by an “objectified” mechanistic conception of matter) paints of the natural world presents it as devoid of the sensory qualities and of anything personal. And yet the picture itself exists only within the minds of persons – scientists themselves – and takes as its evidential base the senses, and thus the very sensory qualities it refuses to locate in nature.

This epistemological paradox was a major theme of E. A. Burtt’s The Metaphysical Foundations of Modern Physical Science (Burtt being, as I have noted before, one of several major early twentieth-century scholars who emphasized the problematic character of the mechanistic revolution, before this theme went down the academic memory hole sometime in the 1960s). But awareness of it goes back much farther than that – indeed (and as Schrödinger reminds us) all the way back to the 5th century B.C., and in particular to Democritus, one of the fathers of atomism. In a famous fragment, Democritus imagines a conversation between the intellect, which (as Democritus naturally assumed) must endorse the atomists’ banishment of the sensory qualities from nature, and the senses, which form the evidential basis for the atomist theory:

Intellect: “Color is by convention, sweet by convention, bitter by convention; in truth there are but atoms and the void.”

Senses: “Wretched mind, from us you are taking the evidence by which you would overthrow us? Your victory is your own fall.”

It must be emphasized that Democritus is, commendably, calling attention to a difficulty facing a theory that he himself endorses; and that we have no idea how, or even if, he tried to resolve it. It is by no means obvious that any materialist in the intervening millennia has done any better. Many of them have done worse; indeed, vulgar materialists of the New Atheist stripe typically show no awareness that there is a problem here in the first place. Unfortunately, this includes Daniel Dennett, a well-known philosopher of mind. Dennett explicitly endorses an eliminativist position vis-à-vis the sensory qualities (see e.g. his essay “Quining Qualia”) – which is to his credit insofar as (I would argue) any consistent materialist must ultimately be an eliminativist anyway. What is not to his credit is his utter blindness to the deep philosophical puzzles such a position opens up, his peddling of shameless caricatures of anti-materialist views, and in general his refusal to concede that opponents of materialism are motivated by serious philosophical concerns.

Schrödinger provides us with a plausible account of the origins of this sort of blindness (in scientists, anyway – philosophers like Dennett should know better). In “The Mystery of the Sensual Qualities” he writes:

Scientific theories serve to facilitate the survey of our observations and experimental findings. Every scientist knows how difficult it is to remember a moderately extended group of facts, before at least some primitive theoretical picture about them has been shaped. It is therefore small wonder, and by no means to be blamed on the authors of original papers or of text-books, that after a reasonably coherent theory has been formed, they do not describe the bare facts they have found or wish to convey to the reader, but clothe them in the terminology of that theory or theories. This procedure, while very useful for our remembering the facts in a well-ordered pattern, tends to obliterate the distinction between the actual observations and the theory arisen from them. And since the former always are of some sensual quality, theories are easily thought to account for sensual qualities; which, of course, they never do. (p. 164)

In the case at hand, neuroscientists who begin, as every empirical scientist must, with observations – that is to say, with conscious experiences whose character is determined by various sorts of qualia or sensory qualities – go on to construct a theoretical description of the physical and neural processes associated with perception. This theoretical description then takes on, as it were, a life of its own, coming to seem as real or even more real than the concrete experiences that led to it, and the language in which the former is couched comes to be applied to the theorist’s description of the latter. Thus an explanation of “heat” in the sense of molecular motion comes to seem, especially when coupled with neuroscientific data, an explanation of “heat” in the sense of a certain kind of tactile sensory quality; an explanation of “red” in the sense of light of a certain wavelength comes to seem an explanation of “red” in the sense of a certain kind of visual sensory quality; and so forth.

But this is a muddle, a subtle committing of the fallacy of equivocation. The key theoretical concepts – molecular motion, light wavelengths, neural firing patterns, and so forth – are always understood in light of a broadly mechanistic conception of the natural world which follows the early moderns’ project of excluding final causes, sensory qualities and the like from matter and redefining it in abstract mathematical terms. To “explain” sensory qualities or qualia in such “scientific” (i.e. mechanistic and “objectified”) terms is thus really to change the subject. Earlier generations of philosophers and scientists realized this, which is why few of them were materialists – they saw that, by definition as it were, sensory qualities could not be “material” given the new conception of matter. But later generations – especially the current generation of scientists, who tend to be far more specialized and often seem less philosophically-minded or philosophically-educated than their predecessors – have forgotten this conceptual history. And this forgetfulness and philosophical shallowness together with the practical successes of modern science have hardened many of them – or at least the more vocal of the pop science writers among them – into a crude scientism which assumes that there are no philosophical problems, or at least no serious ones, which science is not capable of answering.

Thus, when philosophers come along – whether dualists or the more sophisticated and fair-minded sort of naturalist (e.g. a Searle, a Nagel, or a Chalmers) – and point out that existing neuroscientific “explanations” of consciousness and the like do not in fact explain the relevant phenomena at all, it comes to seem like these philosophers are inventing a new problem in a desperate and obscurantist attempt to salvage a belief in human dignity and specialness. In fact they are simply calling attention to a very old problem that the mechanistic theoretical model itself has created, and of which earlier generations of philosophers and scientists were well aware. In fact it is scientism which fosters obscurantism, ignoring as it does clear conceptual distinctions and forcing all intellectual life into a methodological procrustean bed. And in fact the mechanistic “objectified” conception of matter inherited from the early moderns is not a scientific discovery at all but a philosophical posit, and one which creates philosophical problems rather than solves them.

Obviously I am not claiming to establish these large claims here. (Doing so is in large part what The Last Superstition is about.) And obviously there are different moves a materialist might try to make in order to get around the problems in question (though, equally obviously, I don’t myself think any such moves can succeed). The point is that the problems are real ones, and serious ones. Any naturalist who dismisses them as motivated by irrational religious fanaticism is either ignorant or dishonest; certainly Democritus, Schrödinger, Burtt, Searle, Nagel, Chalmers et al. have no theological ax to grind. It goes without saying that our knowledge of the human brain has come a very long way since the 5th century B.C. But philosophically speaking, the history of materialism from Democritus to Dennett marks a precipitous decline.

Addendum 9/14: It occurs to me on re-reading the post that the Chalmers reference in the first sentence of the second-to-last paragraph is, coupled with the “or,” unintentionally misleading: Chalmers is a naturalist, but he is also a dualist of sorts. My apologies. The conceptual lay of the land vis-à-vis this subject is extremely complex, the range of possible positions is very large, and it is difficult briefly to summarize the issues without oversimplification – especially when (as was the case with this post) one is writing late on a Saturday night!

Animals are conscious! In other news, sky is blue, water wet

A reader calls my attention to a Discovery News story which breathlessly declares: 

A prominent group of scientists signs a document stating that animals are just as “conscious and aware” as humans are.  This is a big deal.

Actually, it is not a big deal, nor in any way news, and the really interesting thing about this story is how completely uninteresting it is.  Animals are conscious?  Anyone who has ever owned a pet, or been to the zoo, or indeed just knows what an animal is, knows that.  

OK, almost anyone.  Descartes notoriously denied it, for reasons tied to his brand of dualism.  And perhaps that is one reason someone might think animal consciousness remarkable.  It might be supposed that if you regard the human mind as something immaterial, you have to regard animals as devoid of consciousness, so that evidence of animal consciousness is evidence against the immateriality of the mind and thus a “big deal.”  This is not what the article says, mind you, but it is one way to make sense of why it presents the evidence of animal consciousness as if it were noteworthy.

Nagel and his critics, Part VIII

Resuming our series on the serious critics of Thomas Nagel’s Mind and Cosmos, let’s turn to Simon Blackburn’s review in New Statesman from a few months back.  Blackburn’s review is negative, but it is not polemical; on the contrary, he allows that the book is “beautifully lucid, civilised, modest in tone and courageous in its scope” and even that there is “charm” to it.  Despite the review’s now somewhat notorious closing paragraph (more on which below) I think Blackburn is trying to be fair to Nagel.

Vallicella on hylemorphic dualism, Part III

Bill Vallicella and I have been debating Aquinas’s hylemorphic dualism (HD).  Earlier posts (here, here, here, and here) have focused on Aquinas’s motivations for combining hylemorphism and dualism.  As we continue Bill and Ed’s Excellent Adventure, the discussion turns to questions about the internal coherence of the view.  In a new post, Bill summarizes what he takes to be one of the main problems with HD.  Give it a read, then come back.

How to animate a corpse

One of the downsides of being a philosopher is that it makes it harder to suspend disbelief when watching horror flicks.  Plot holes become more glaring and speculations seem wilder when one’s business is looking for fallacies.  On the other hand, there is nothing so absurd but some philosopher has said it; hence there’s no one better placed to find a way to make even the most preposterous yarn seem at least remotely plausible.  A case in point, submitted for your approval: My take on a segment from Rod Serling’s Night Gallery, adapted from H. P. Lovecraft’s short story “Cool Air.”  (You can find it on Hulu and YouTube.)  Watching it for the first time recently, I was annoyed by what at first seemed to me an obviously nonsensical twist ending.  On further reflection, there is a way to make sense of it, if one makes the appropriate metaphysical assumptions.

Nagel and his critics, Part VII

Let’s return to our look at the critics of Thomas Nagel’s Mind and Cosmos.  New commentary on Nagel’s book continues to appear, and to some extent it repeats points made by earlier reviewers I’ve already responded to.  Here I want to say something about Mohan Matthen’s review in The Philosophers Magazine.  In particular, I want to address what Matthen says about the issue of whether conscious awareness could arise in a purely material cosmos.  (Matthen has also commented on Nagel’s book over at the New APPS blog, e.g. here.)

Two, four, six, eight! Who do you reincarnate?

Could there be such a thing as reincarnation?  A necessary condition would be the truth of some form of dualism.  So far so good, since (I would say) some form of dualism is true.  But which form?  There are at least three to choose from: substance dualism, the version associated with Plato and Descartes; property dualism, associated with the likes of John Locke, David Chalmers, and (the early) Frank Jackson; and the hylemorphic dualism defended within the Aristotelian-Thomistic metaphysical tradition.  Are all of these equally favorable to a defense of reincarnation?

Knowing an ape from Adam

On questions about biological evolution, both the Magisterium of the Catholic Church and Thomist philosophers and theologians have tended carefully to steer a middle course.  On the one hand, they have allowed that a fairly wide range of biological phenomena may in principle be susceptible of evolutionary explanation, consistent with Catholic doctrine and Thomistic metaphysics.  On the other hand, they have also insisted, on philosophical and theological grounds, that not every biological phenomenon can be given an evolutionary explanation, and they refuse to issue a “blank check” to a purely naturalistic construal of evolution.  Evolutionary explanations are invariably a mixture of empirical and philosophical considerations.  Properly to be understood, the empirical considerations have to be situated within a sound metaphysics and philosophy of nature.

Jackson on Popper on materialism

While we’re on the subject of mind-body interaction, let’s take a look at Frank Jackson’s article on Karl Popper’s philosophy of mind in the new Cambridge Companion to Popper, edited by Jeremy Shearmur and Geoffrey Stokes.  Popper was a dualist of sorts, and Jackson’s focus is on the role Popper’s “World 3” concept and the issue of causal interaction played in his critique of materialism.

Hayek and Popper

My paper “Hayek, Popper, and the Causal Theory of the Mind” appears in the latest volume of Advances in Austrian Economics, a special issue edited by Leslie Marsh and devoted to the theme Hayek in Mind: Hayek’s Philosophical Psychology.  The publisher’s web page for the volume is here.  You can find Marsh’s website devoted to the book here, the table of contents here, and Marsh’s introduction to the volume here.  Here’s the abstract of my article (which follows the publisher’s required abstract format):

Some brief arguments for dualism, Part III

In the previous post in this series, I argued that the “mechanistic” conception of the natural world adopted by the early modern philosophers more or less entails a kind of dualism insofar as its banishment of final causes from the material world effectively makes intentionality necessarily immaterial. Intentionality, of course, is one of two features of the mind to which contemporary philosophers of mind have paid special attention. The other is consciousness, and in particular the “qualia” that are said to make consciousness uniquely difficult to explain in material terms. There is a good reason for this difficulty – indeed, impossibility – and it is the same reason why intentionality is impossible to explain in materialistic terms. It lies in the mechanistic conception of matter itself.

The early modern philosophers and scientists were obsessed with quantification. There were several reasons for this, one of them being their desire to reorient intellectual efforts toward the improvement of life in this world and away from the otherworldliness of the ancients and medievals. This entailed a new emphasis on technology and more generally on the control and exploitation of the natural world in the interests of bettering man’s material condition. Since quantification would facilitate this, those aspects of nature that could be described in purely mathematical terms took on a special importance, and those which could not came to seem, from the point of view of this new, worldly approach to learning, irrelevant at best and a distraction at worst. Thus did final causes, hidden powers, substantial forms and the like go out the window. So too did the qualitative aspects of nature. Colors, odors, tastes, feels, sounds, and the like, at least as understood by common sense, vary from observer to observer – think of old philosophical chestnuts like the room temperature water that feels warm to one hand and cool to the other, colorblindness, and so forth – making them a poor fit for a science looking to make nature subject to human prediction and control. Out the window with them too, then. The physical world would be redefined as comprised of colorless, odorless, tasteless particles in motion; and color, temperature, and the like would be redefined entirely in terms of the quantifiable relations holding between these particles (e.g. heat and cold in terms of molecular motion). What about color, odor, taste, and so forth as common sense understands them? They in turn were redefined as entirely mind-dependent “secondary qualities” (or rather, ideas of secondary qualities), the ancestors of the contemporary philosopher’s concept of qualia. On the view in question, they do not exist in the physical world as it is in itself, but only in our perceptual representation of that world.

It should be obvious, then, how, as with intentionality, the notion that qualia are incapable of materialistic explanation is not some desperate attempt to avoid the implications of modern science, but is rather precisely a consequence of modern science. The mechanistic conception of matter that underlies science (or rather underlies what, since the 17th century, is allowed to count as science) itself entails that qualia (as we call them today) are immaterial or non-physical. Many early modern thinkers – Descartes, Cudworth, and Locke, for example – saw this, which is part of the reason they were dualists. Given the mechanistic conception of matter, these thinkers concluded that “secondary qualities,” “sensory qualities,” “qualia,” or whatever else you want to call them are necessarily immaterial, precisely because matter got (re)defined by the mechanical philosophy by contrast with these qualities.

Some contemporary naturalists – Joseph Levine, Thomas Nagel, and John Searle, for example – have more or less recognized this, acknowledging that there is nothing more to the contemporary materialist’s concept of matter (which derives from the 17th century “mechanical” conception) other than its contrast with the “qualitative” (and intentional) features of our experience of the world. Precisely for this reason, all three of these thinkers have (in their different ways) regarded modern materialism as deeply conceptually problematic, though they have also stopped short of embracing dualism. But other contemporary naturalists – Dennett and the Churchlands, for example, not to mention countless lesser lights of the sort who write crude atheist pamphlets and pop neuroscience books – cluelessly suggest that there is no good reason to think that the mind will fail to yield to the same sort of reductive explanation in terms of which everything else in nature has been accounted for.

In fact there is a very good reason why the mind should be uniquely resistant to such “explanation,” and it precisely because everything that doesn’t fit the mechanistic-cum-quantificational picture of the natural world has not been “explained” by science at all, but simply swept under the rug of the mind and treated as a mere “projection.” This is true in particular of anything in nature that seems to smack of final causality or to have an irreducible qualitative (as opposed to quantitative) character. It is conceptually impossible that the mind itself should be “explained” in the same way – that is to say, by further sweeping – which is why modern philosophy has a “mind-body problem” of a sort that did not exist before the mechanistic revolution, and why all materialist attempts to “explain” the mind are really disguised versions of eliminative materialism. The tiresome canard that “everything else has already been explained in materialistic terms” is thus a gigantic shell game, pure sleight of hand, a complete fraud from start to finish. (This is a theme I first explored in my book Philosophy of Mind and develop at length in The Last Superstition.)

In any case, we have now a third brief argument for dualism, which can be summarized as follows: Given the materialist’s own (mechanistic-cum-quantificational) conception of matter, colors, odors, tastes and the like as we experience them do not exist in the material world itself; but these qualities do exist in our perceptual representations of the material world; therefore, there exist features of the world – namely these sensory qualities or “qualia” that characterize our perceptual experiences – that are not material or physical features.

Obviously this argument raises questions about how these immaterial features relate to the material ones – Are they basic or emergent? How can they causally interact with the material ones? Do they inhere in a physical or a non-physical substance? – but the fact that it raises them has no bearing on the cogency of the argument itself. My own view is that the standard (Cartesian) dualist answers to such questions are problematic precisely because they buy into the same mechanistic conception of matter to which materialists are beholden. The right approach is to challenge that conception of matter, and return to the Aristotelian-Scholastic picture it replaced. But whether I am right about this or not is also irrelevant to the argument just given, which does not assume any Aristotelian-Scholastic premises, but simply draws out the consequences of the very conception of matter to which materialists themselves are committed. Whatever the deficiencies of Cartesian dualism, they do not approach the sheer incoherence and cluelessness of contemporary materialism.

Rucker’s Mindscape

In his book Infinity and the Mind  (which you can read online at his website), Rudy Rucker puts forward the notion of what he calls the “Mindscape.”  He writes:

If three people see the same animal, we say the animal is real; what if three people see the same idea?

I think of consciousness as a point, an “eye,” that moves about in a sort of mental space.  All thoughts are already there in this multi-dimensional space, which we might as well call the Mindscape.  Our bodies move about in the physical space called the Universe; our consciousnesses move about in the mental space called the Mindscape.

When Frank jilted Mary

We had reason recently to allude to Frank Jackson’s famous “knowledge argument” against physicalism. You’ll recall that the argument goes like this: Physicalism claims that if you know all the physical facts that there are to know about people, then you know all the facts there are to know about them, period; for human beings are (says the physicalist) entirely physical. But now consider Mary, a master neuroscientist of the future. Mary has lived her entire life in a black and white room, and has never had any experiences of colors. Still, having studied all the relevant neuroscientific literature, she knows everything there is to know about the physics and physiology of color perception. Hence she knows, for example, everything there is to know about what goes on in someone’s brain when he sees a red object, everything there is to know about the surface reflectance properties of red objects, and so forth. Now imagine that she leaves her black and white room and sees a red object herself for the first time. Does she learn something new? Surely she does – she learns what it’s like to see red. But then, physicalism is false. For though Mary knew all the physical facts about human perceptual experience before she left the room, she didn’t know all the facts, since she learned something when she left the room. Hence there are facts about human nature, and in particular facts about conscious experience, that escape the physicalist story – namely facts about “qualia,” the subjective features of a conscious experience in virtue of which there is “something it is like” to have that experience.

Jackson first presented this argument is his 1982 paper “Epiphenomenal Qualia,” and repeated it in 1986 in “What Mary Didn’t Know.” (There were several precursors to the argument, such as Thomas Nagel’s “What is it like to be a bat?”, and similar but independently developed ideas, such as Howard Robinson’s deaf scientist example in his 1982 book Matter and Sense.) The argument has generated an enormous literature. Some of it is collected in the Ludlow, Nagasawa, and Stoljar edited volume There’s Something About Mary: Essays on Phenomenal Consciousness and Frank Jackson’s Knowledge Argument. You will find there also some later essays by Jackson in which he expresses second thoughts about the argument; for by the late 1990s he had recanted and embraced physicalism.

Why? For no good reason, in my view; nor in the view of Jackson’s fellow “knowledge argument” proponent Howard Robinson, whose (characteristically excellent) essay “Why Frank Should Not Have Jilted Mary” offers a penetrating critique of Jackson’s current views. (You can read part of Robinson’s article here, though the anthology in which it appeared – Edmond Wright’s The Case for Qualia – is well worth the purchase price.)

As Stoljar and Nagasawa note in their introduction to There’s Something About Mary, “the argument, [the later Jackson] said, contained no obvious fallacy, and yet its conclusion – that physicalism is false – must be mistaken” (p. 23). Again, why? We might distinguish two components of Jackson’s current position. First, there is Jackson’s justification for claiming that something or other must be wrong with the knowledge argument, even if it seems to be perfectly cogent; and second, there is his strategy for explaining away the apparent cogency of the argument by suggesting where a fallacy is most likely to be found in it. The second component involves appeal to a “representationalist” theory of consciousness, and interested readers will find in Robinson’s essay a useful discussion of the problems with Jackson’s application of this theory. (For my money the main problems are two: First, representationalism is, at the end of the day, merely a riff on functionalism, and thus cannot serve to rebut the knowledge argument any more than – by Jackson’s own lights pre-recantation – older versions of functionalism could. Second, the key notion of “representation” itself cannot be accounted for in physicalist terms, so that even a successful representationalist analysis of consciousness could not vindicate physicalism.)

But it is the first component of Jackson’s current position – and some remarks of Robinson’s that are relevant to it – that I want to focus on here. In his 2002 essay “Mind and Illusion” (available in the Ludlow, Nagasawa, and Stoljar volume), Jackson tells us that:

Much of the contemporary debate in the philosophy of mind is concerned with the clash between certain strongly held intuitions and what science tells us about the mind and its relation to the world. What science tells us about the mind points strongly towards some version or other of physicalism. The intuitions, in one way or another, suggest that there is something seriously incomplete about any purely physical story about the mind.

For our purposes, we can be vague about the detail and think broadly of physicalism as the view that the mind is a purely physical part of a purely physical world. Exactly how to delineate the physical will not be crucial: anything of a kind that plays a central role in physics, chemistry, biology, neuroscience, and the like, along with the a priori associated functional and relational properties, count, as far as we are concerned.

Most contemporary philosophers, when given a choice between going with science and going with intuitions, go with science. Although I once dissented from the majority, I have capitulated and now see the interesting issue as being where the arguments from the intuitions against physicalism – the arguments that seem so compelling – go wrong. (p. 421)

This is a remarkable passage – remarkable for the breathtaking rhetorical sleight of hand it embodies. I do not mean to imply that Jackson is being insincere or intentionally manipulative of his readers; I am sure he is not. But – with all due respect to a philosopher whose work I have long admired, and still admire – that is only because he has evidently now “drunk the Kool-Aid” of physicalism so deeply that he is perhaps incapable of seeing how thoroughly tendentious and question-begging is his characterization of the philosophical situation.

Consider the way Jackson frames the issue here – as a debate between “science” and “intuition.” If that really were what the debate is about, how could any rational person fail to understand why Jackson has come to endorse physicalism? Indeed, how, in that case, could any rational person fail to join him in that endorsement? But in fact that is not what the debate is about; certainly Jackson has given us no reason to think it is. Jackson’s younger self certainly didn’t appeal to “intuition.” There is no such appeal in the formulation of the knowledge argument I presented above, and there is no such appeal in Jackson’s presentation in the two articles in which he first put forward the argument. Indeed, in “Epiphenomenal Qualia,” Jackson explicitly says that it is “unfair” to suggest that a qualia-based objection to physicalism must rest on an unargued intuition, explicitly distances himself from the “modal argument” against physicalism precisely because he takes it to rest on a disputable intuition, and explicitly favors the knowledge argument precisely because he there takes it to embody something more firm than an appeal to disputable intuitions!

Consider too that both sides can play the game Jackson is playing in the passage under consideration. The anti-physicalist could say:

We know from the very nature of “the physical” as that tends to be understood in contemporary philosophy that there can in principle be no physicalistic explanation of conscious experience. Arguments like the knowledge argument illustrate this point. And yet many contemporary philosophers have a strongly held intuition that a scientific view of the world requires a commitment to physicalism. Still, other contemporary philosophers, when given a choice between going with solid philosophical arguments and going with disputable intuitions, go with the solid philosophical arguments. Accordingly, they reject physicalism as a misinterpretation of science.

Is this as plausible as Jackson’s way of framing the issue? I maintain that it is far more plausible. And this brings us to the other problem with the passage from Jackson under consideration. Jackson casually assures us that “what science tells us about the mind points strongly towards some version or other of physicalism.” Physicalists say this all the time, of course. But it isn’t true, and Jackson certainly gives us no reason whatsoever to think that it is true. In fact, modern science points solidly away from physicalism, and the reason has precisely to do with the very issue Jackson thinks is “not crucial,” viz. “exactly how to delineate the physical.” For as I have noted in many places – most recently in a post on Chomsky – notions like “matter” and “the physical,” though they have (as Chomsky has rightly emphasized) at best a very elusive positive content in most modern thinking on the mind-body problem, nevertheless have also a very clear negative content. As I stated in the Chomsky post:

Whatever matter turns out to be, there are certain features that modern philosophers, and scientists in their philosophical moments, tend to refuse ever to attribute to it.

For at least some of them, this would seem to include sensory qualities like color, odor, taste, sound, and the like as common sense understands them. For the mechanistic revolution Chomsky alludes to was not merely, and indeed not even essentially, committed to the idea that material causation involves literal contact. It was also and more lastingly committed to some variant or other of a “primary/secondary” quality distinction on which there is nothing in the material world that “resembles” our “ideas” of the sensory qualities mentioned (as Locke would put it). If we want to redefine the “red” of a fire engine in terms of how its surface reflects photons at certain wavelengths, we can say that the fire engine is red. But if by “red” we mean the way red “looks” to us when we perceive it, then nothing like that exists in the fire engine, which is (if we think of color in these commonsense terms) intrinsically “colorless.” And so on for sounds, tastes, and all the rest. Color, odor, taste, sound, and the like – again, as common sense understands them (rather than as redefined for purposes of physics) – are reinterpreted by mechanism as projections of the mind, existing only in consciousness. This is the origin of the “qualia problem,” and the puzzle now becomes how to relate these “qualia” or “phenomenal properties” to the intrinsically colorless, odorless, tasteless particles that make up the brain just as much as they do external material objects.

Now if one insists on denying these sensory qualities to matter, then it seems clear that we do have a clear enough conception of “body” to generate a mind-body problem. More than that, we have a conception that clearly implies that the mind (in which alone these qualities exist) cannot be something material or bodily – that, at any rate, is the lesson drawn by early modern thinkers like Cudworth and Malebranche, and by contemporary writers like Richard Swinburne, who take the “mechanistic” conception of matter itself to entail dualism.

This lesson, I submit, is precisely what Jackson’s original knowledge argument illustrates. It shows in a new way what early modern philosophers like Descartes, Cudworth, Malebranche, and Locke, and contemporary thinkers like Nagel and Swinburne, already knew and pointed out many times over the centuries – that given the (mechanistic) understanding of “the physical” that all modern philosophers (whether they be Cartesians, idealists, or materialists) tend to take for granted, a “physicalistic” explanation of consciousness is in principle impossible. It is the moderns’ very conception of matter, rather than some “disputable intuition,” that opens the way to dualism. And insofar as modern science has committed itself to this conception of matter, it follows that modern science itself points to dualism and away from physicalism. I hasten to add, though, that this commitment is not really a “scientific” commitment at all, but a purely philosophical one.

And a mistaken one too, from the point of view of Aristotelian-Thomistic philosophers like myself. This brings me to some important remarks from Robinson’s essay. Robinson says:

The dialectical situation in which the knowledge argument is usually taken to be located is the following: it is accepted that physicalism gives an adequate account of non-conscious reality, which constitutes almost 100 percent of the universe, but struggles to accommodate certain features of mental life, namely the “what it’s like” or qualia of certain conscious states. These latter constitute “the hard problem” for physicalism. The fact that they also constitute such a tiny part of the world is presented as a reason for thinking that they cannot plausibly be held to refute a unified physicalist account.

I think that this constitutes a radical misunderstanding of the dialectical situation. What the argument really brings out is that only experience of the appropriate kind can reveal the qualitative, as opposed to purely formal and structural, features of the world. The kind of thing that Mary did not know, generalized from color vision to all the other sensible qualities, is essential to any contentful conception of the world, and physicalism without it would lack any empirical content. (p. 240)

There are two themes here that I want briefly to develop. The first is the entirely illusory character of the widespread assumption that “everything else has been given a physicalistic explanation,” so that the mind cannot plausibly be regarded as immune to such explanation. In fact, the reason it seems that “everything else has been given a physicalistic explanation” is precisely the reason that the mind cannot be “explained” in the same way. For “everything else” has been “explained” in a physicalistic manner precisely by carving off the aspects of mind-independent reality that do not fit the physicalistic model and relocating them in the mind, treating them as mere projections. Again, color, odor, sound, taste, heat, cold, and the like, as common sense understands them, were “explained” only by denying that these qualities really exist in the external physical world at all in the first place. Instead, color, odor, sound, and the rest were for purposes of physics redefined in physicalistically “respectable” terms – color in terms of surface reflectance, sound in terms of compression waves, and so on. Color, sound, etc. as common sense understands them were then reinterpreted as existing only in our conscious experience of the material world, rather than in the material world itself. In short, they are not truly “explained” at all, but just swept under the rug of the mind. (As I have argued before, the problem intentionality poses for physicalism has a similar origin.)

The early moderns generally recognized that this entails a kind of dualism – that it is simply incoherent to suppose that one can get rid of the sensory qualities so reinterpreted by further relocation and redefinition, any more than one can get rid of literal dirt that one has swept under a rug by further application of the “sweep it under the rug” strategy. Contemporary writers like Thomas Nagel see this too – see that it is precisely the physicalist’s own understanding of what “reductive explanation” involves that precludes in principle a “reductive explanation” of conscious experience itself. But contemporary physicalists, forgetful of the history of their discipline, cluelessly draw precisely the opposite conclusion: “Come on, we’ve gotten rid of all the other dirt in the room by sweeping it under the rug; so why wouldn’t we be able to deal with the dirt under the rug in the same way?”

The second theme from Robinson I want to call attention to is his suggestion that “only experience of the appropriate kind can reveal the qualitative, as opposed to purely formal and structural, features of the world.” What he is getting at is this. When the natural world is denuded of the qualitative features common sense takes it to have – color, odor, taste, sound, and the like, as we experience them in everyday life – what we are left with is an entirely abstract structure, the sort of thing physics expresses in the language of mathematics. But it is simply incoherent to regard the mind-independent world as nothing but an abstract structure; there must be something which has the structure. Moreover, to deny the existence of the qualitative features themselves – as some eliminative materialists have suggested doing as a way of “solving,” by brute force, the problem qualia pose for physicalism – would in effect be to cut off the scientific redefinition of nature from any empirical support at all. We would be denying, in the name of science, the very existence of the conscious experience from which scientific inquiry proceeds (a paradox that was not lost on the ancient Greek atomist Democritus, as I noted in an earlier post).

Bertrand Russell, E. A. Burtt, and other early twentieth-century thinkers were well aware of these problems. Russell’s solution was to suggest that the sensory qualities which the moderns had redefined as mere projections of the mind have to be put back into the natural world after all. Accordingly, something like what philosophers now call “qualia” were, for Russell, the intrinsic features of the external physical world – that which “fleshes out” or makes concrete the otherwise abstract structure described by physics. Contemporary philosophers like Michael Lockwood, David Chalmers, and Galen Strawson have followed Russell’s lead, and Robinson’s position seems to bear a family resemblance to theirs. The trouble is that, given the “mental” character modern philosophers tend to attribute to the sensory qualities, this Russellian approach seems to lead to a kind of idealism or panpsychism, on which the natural world is mental through and through (though Russell and Lockwood, at least, try to resist this consequence). This is, I think, a less mad view than physicalism is, but it is mad all the same.

From an Aristotelian-Thomistic point of view, the mistake was opting for a mechanistic-cum-quantitative conception of nature in the first place, and philosophers of mind have been on the wrong track ever since Descartes, Hobbes, and Co. The value of the knowledge argument is that it shows, as Robinson puts it, that “classical physicalism is broken-backed from the start” (p. 243). But Cartesian dualism, property dualism, idealism, panpsychism, etc. are at best only less bad than physicalism. The correct remedy is a full-blown return to Aristotelian-Thomistic hylemorphism, on which alone the quantitative picture of the world presented to us by modern science can properly be understood – as an important part of the correct story about the natural world, but never the whole story.

Cartesian angelism

Angels, as Aquinas and other Scholastic theologians conceive of them, are purely intellectual substances, minds separated from matter.  An angel thinks and wills but has no corporeal operations at all.  Naturally, then, popular images of angels – creatures with wings, long flowing robes, and so forth – have nothing to do with the real McCoy.  For a modern philosopher, the easiest way to understand what an angel is is to conceive of it as a Cartesian res cogitans – though as we will see in what follows, in a way this actually gets things the wrong way around.

The last enemy

There are two sorts of people who might be tempted to think of death as a friend: those who think the nature of the human person has nothing to do with the body, and those who think it has everything to do with the body; in short, Platonists and materialists.  Protestant theologian Oscar Cullmann summarizes the Platonist’s position in his little book Immortality of the Soul or Resurrection of the Dead? as follows:

Give me that old time atheism

Last night I was dipping into Roy Abraham Varghese’s Great Thinkers on Great Questions, an interesting collection of interviews with a number of prominent philosophers (including A. J. Ayer, G. E. M. Anscombe, Alvin Plantinga, Richard Swinburne, Ralph McInerny, Brian Leftow, Gerard Hughes, and many others) on topics mostly related in one way or another to religion. Some of Ayer’s remarks brought to mind how different earlier generations of agnostics and atheists had been, not merely culturally (as Roger Scruton has noted) but philosophically. Ayer, though a notorious lifelong foe of religion, was not a materialist. In his famous book Language, Truth, and Logic, he attempted (as he reminds us in the Varghese volume) to reduce physical objects to “sense-contents,” entities which were intended to be neutral between mind and matter but which were in fact (as Ayer admits) closer to the mental than to the physical side of the traditional mental/physical divide. Hence the resulting position was “much more nearly mentalistic than physicalistic.” And to the end of his life he apparently always rejected any attempt to reduce the mental to the physical.

The reason for this is that even agnostic and atheist philosophers of Ayer’s generation generally recognized that materialism is just prima facie implausible. As I have noted in some earlier posts (here and here), and as I discuss at length in The Last Superstition, dualism was by no means a deviation from the broadly mechanistic conception of matter contemporary philosophy has inherited from the 17th century, but rather a natural consequence of that conception, given its highly abstract and mathematical redefinition of the material world. If matter is what the mechanistic view says it is, then (it seems) there is simply nowhere else to locate color, odor, taste, sound, etc. (as common sense understands these qualities, anyway), and nowhere else to locate meaning (given the banishment of final causes from the material world), than in something immaterial. And until about the 1960s, most philosophers (the occasional exception like Hobbes notwithstanding) seemed to realize that, short of returning to an Aristotelian hylemorphic philosophy of nature, the only plausible alternatives to dualism were views that tended to put the accent on mind rather than on matter – such as idealism, phenomenalism, or neutral monism.

The last of these, as its name implies, was officially committed to the view that the basic stuff out of which the world is constructed is “neutral” between mind and matter, but notoriously it tends to collapse into either phenomenalism or idealism. In my atheist days, it was the version of neutral monism developed by Bertrand Russell (or rather a riff on that version developed by F. A. Hayek) that I took to be the most plausible approach to the mind-body problem. (In recent philosophy, Russell’s views have been developed, in a way that seeks to avoid any sort of idealism, by Michael Lockwood; and, in a way that to some extent or other concedes their idealistic implications, by Galen Strawson and David Chalmers. In my Russellian days I was more attracted to Lockwood’s approach.) After a brief flirtation with materialism while an undergrad, I was more or less inoculated against it by John Searle’s writings, and came to regard the Russellian approach as the most plausible way to defend a naturalistic (if non-materialistic) view of the world.

Most naturalistic philosophers are not at all attracted to this approach, however, precisely (I would suggest) because of its tendency to collapse into some sort of philosophical idealism. For to make mind out to be the ultimate reality is – as the history of 19th century idealism shows – to adopt a view which must surely strike most naturalists as “too close for comfort” to a religious view of the world. To be sure, Chalmers and Strawson do not take their position in anything like a religious direction, but so far few other naturalists have been willing to follow them.

But if they were wise, they would do so. Chalmers and Strawson are in fact among the most interesting philosophers of mind writing today, in part because of their attempt to defend a kind of naturalism while acknowledging the very deep philosophical difficulties inherent in materialism. (Strawson famously dismisses materialism as “moonshine.”) As I have been lamenting in recent posts, most contemporary philosophical naturalists (to say nothing of non-philosophers who are naturalists, such as the New Atheists) have only the most crude understanding of the theological views they dismiss so contemptuously. In the same way, they tend also to be absurdly overconfident about the prospects of a materialist or physicalist account of the mind.

Earlier generations of philosophical atheists or agnostics – Ayer, Russell, Popper, to name just three – knew how difficult it is to defend such an account, and thus avoided grounding their atheism or agnosticism in a specifically materialist metaphysics. Some of their contemporary successors – Lockwood, Chalmers, Strawson, Nagel, Searle, Fodor, McGinn, Levine, among others – have, to varying degrees, some awareness of the same problems. Consequently, at least some of these people realize that naturalism itself (which seems most plausible precisely when spelled out in materialist terms) is by no means obviously right; it is something that requires a very great deal of effort to defend, and cannot blithely dismiss its rivals. Unfortunately, the bulk of contemporary philosophical naturalists – Dennett and Rey being by no means idiosyncratic in this regard – seem forever lost in their dogmatic slumbers.

ADDENDUM: I should note that Strawson does sometimes call his version of Russell's position "real materialism," and that Lockwood has occasionally said similar things. By contrast, Grover Maxwell, another Russellian who influenced both Lockwood and Strawson, repudiates any kind of "materialist" label even though his views are more or less identical to theirs. And Chalmers sometimes characterizes his own variation on Russellianism as a kind of "dualism"! So, the terminology here can get confusing. The point is that all of these authors reject materialism in the standard (Smart, Armstrong, early Putnam, Davidson, Dennett, Churchland, et al.) sense.