The naturalistic world-view is supposed to be a safe haven because of its apparent methodological superiority over its actual and imaginary rivals. The historical background idea, which lends genealogical and psychological support to this confidence, is the notion that modernity is clearly an overall cultural progress accompanied, if not actually triggered by, an early modern scientific revolution stereotypically associated with Galileo and Newton.11 They are seen as decisive, revolutionary cuts in the history of human thought because their discoveries reveal a gap hitherto largely covered up by an ancient, Aristotelian conception of science and nature.
The gap consists in a thorough distinction between how things appear to us as human observers of nature and nature itself. As human observers we are prone to believe that physical objects have smoothly colored surfaces regardless of how they appear to us; we believe in dusk and dawn and in heaven understood as a luminous sphere through which we can see the movement of astronomical phenomena, a sphere blue or grey during daytime (depending on whether you live in Greece or Germany) and mostly black or grey (again depending on location and season) at night, etc. Even Kant, in his famous remark that what awes him most is “the starry sky above me and the moral law in me” (Kant 2015: 129), is in the grip of a pre-modern illusion, the illusion that the starry sky is above him. Even if there were a starry sky, it would be not above him but all around him. Yet, this would make it look less transcendent, as we tend to point upwards when it comes to mysterious or awe-provoking matters, which is just a bad habit inherited from our less enlightened ancestors.
Wilfrid Sellars has notoriously named the two sides of the gap “the manifest image” and “the scientific image” of man respectively (Sellars 1963). Notice that Sellars does not speak of the manifest and the scientific image tout court, as he wants to emphasize that both images are systematic overall representations of how things hang together “in the broadest possible sense” (ibid.: 1) from the standpoint of a human being. There are, of course, various other ways of labeling and characterizing the gap in question: subjective vs. objective (Nagel 1989); first-person vs. third-person perspective; thick vs. thin concepts (Levine 2004); life-world (Lebenswelt) and science (Husserl 1970), etc. For brevity’s sake let us just speak of “the gap” in order to avoid hasty conceptualizations of the phenomena in question. Most accounts of the gap draw on a genealogical story in order to account for the alleged fact that only modern people became fully aware of it. We moderns are proud discoverers of the gap and we shun anybody who does not share our sense of it.12
On account of the genealogical myths which surround our modern encounter with the gap, the details of the actual story make it hard to see the conceptual core, which will play a central role in due course. Arguably all accounts of the gap rely on a background picture, which I call standard naturalism. Standard naturalism is really a fusion of a number of claims, in particular, a metaphysical claim, an epistemological claim, and two continuity theses.
(SN1) Metaphysical naturalism (materialism): Everything which (really) exists is ultimately material-energetic and therefore woven into the causal web studied by our best natural-scientific practices.
(SN2) Epistemological naturalism: Everything which (really) exists can best be explained with recourse to the standards of theory construction definitive of our best natural-scientific practices.
(SN3) Biological continuity: The human brain/the human mind is part of the natural order. It is a natural kind located on a specific branch of evolution.
(SN4) Methodological continuity: Every genuine explanation has always been governed by the standards made explicit by modern science.
There are other ways of classifying the tenets built into the rather vague structure of the modern scientific world-view.13 In what follows, I will mostly argue against (SN1) and (SN3). Yet, I believe that naturalism fails on all fronts. The human mind is not a natural kind. Only a proper subset of our mentalistic vocabulary picks out natural kinds, even though it is the case that no part of that vocabulary refers to a reality that would have existed had there been no suitable brains or other natural necessary conditions for there to be mental processes in reality.14
Nevertheless, let me emphasize before I get to work that naturalism is based on a wide array of actual facts that need to be respected and typically have been respected all along by many critics of naturalism. To start with, I do not intend to deny that humans are animals and, therefore, in part objects governed by the parameters articulated by evolutionary theory. Neither do I want to deny that Aristotelian physics turned out to be a huge failure. When it comes to the human mind, I am a biological naturalist in the sense of someone who holds that a certain type of brain is a naturally necessary condition for human mindedness, albeit not a sufficient one.15 I am not interested in undermining scientifically established facts, but I am in the business of attacking philosophically misguided interpretations of what natural science has established and can establish in the future with respect to the human mind. Philosophically misguided interpretations of natural science are widespread, both among philosophers and among scientists.
In the next part of this chapter, I will sketch some recent arguments against naturalism, in particular against (SN1) and (SN3). I will then address the pressing question of how to conceive of the human mind after the failures of naturalism. If naturalism does not work, we need an alternative unless we are happy to accept an irresoluble riddle, a view which also has some prominent defenders.16
II Naturalism’s Failures
Let us begin the work of questioning naturalism’s claim to legitimacy with a very natural thought experiment which I will call the New Yorker – based on the cover of the magazine’s issue for March 29, 1976, also known as “View of the World from 9th Avenue.” As I write these lines, I am in Paris, which serves just as well for the thought experiment as New York. Paris is located in France, France is located on the face of the Earth, which is one of the planets orbiting the sun. When I assert these trivialities, I imagine a position from which I am able to assess claims about our location in the universe, such as Google Earth. If I press the minus button on Google Earth long enough, I get to see the Earth. There is a vantage point from which the Earth can be observed.
At this point, let us invent a much more powerful engine: Google Universe. If I press minus in Google Universe, I am in a position to observe the Earth, our solar system, its location in a branch of the Milky Way, the galaxy cluster of which the Milky Way is a part, and eventually the entire universe. But stop! Which position do I occupy when I finally reach the position from which I can assess claims about the structure of the entire universe? Certainly, I cannot coherently imagine a position from which I can observe the entire universe in a way strictly analogous to any position conceivable in a Google Earth format. The standpoint from which I observe the Earth where I am actually located while using Google Earth has a physical location at a certain distance from Earth. Yet, the standpoint from which I observe the entire universe within which I am located cannot have a physical location at a certain distance from the universe, since any such location would be within the universe. It is part and parcel of the standpoint of Google Earth that its standpoint is not on Earth, but it does not make sense to introduce a standpoint that is not in the universe, since it is part of the concept of a standpoint that we can account for its features in terms of basic geometrical and more complicated physical features built into the optical or observer-relative conditions for standpoints. What we know about standpoints is incompatible with the notion that we could conceive of a standpoint outside of the universe from which we could literally observe it.
Against this background, philosophers have criticized the assumptions underpinning the illusion of the possibility of Google Universe, which overextends the notion of a standpoint or point of view. For instance, Hilary Putnam attacks this as a “God’s eye view” (Putnam 1981: 49; 1992: 7), Thomas Nagel has labeled this a “View from nowhere” (Nagel 1989), and
Willard van Orman Quine denies us access to any such “cosmic exile” (Quine 1960: 275–6).
However, metaphysical naturalism or materialism seems to rely on the availability (conceivability) of a view from nowhere, as it makes claims about absolutely everything without being in a position to make justified claims about its own position within the physical totality, which is its object.17
At this point, the would-be materialist might resort to one of the following two options:
argue that Google Universe is conceivable and possible after all;
argue that materialism is not based on such an incoherent scenario.
Arguments for Google Universe might set out from the observation that the standpoint envisaged by Google Universe simply is our standpoint. We learn from the standpoint of Google Universe that we have a location in space-time as a whole, which can be described in terms of physics. We could apply this to Google Earth as well: if we see Earth in Google Earth, we see where we are located. If we see ourselves in the universe as a whole, we do so from within the universe. But this does not solve the problem that there is literally a standpoint from which we can see Earth and realize that we are located on Earth, whereas there is no such standpoint for the universe – at least not for the materialist.18 Thus, this option is ultimately hopeless and unnecessarily reactive.
This is why the materialist had better choose to argue that materialism is not based on an incoherent thought experiment. At this point, she might reply that materialism is a well-established theory based on insights into the overall causal or nomological closure of the universe. The universe is supposed to be governed by natural laws and to harbor physical objects which are defined as material-energetic objects or structures and are all part of a whole, the universe, nature, or the cosmos.
Still, even on this level, materialism is a metaphysical position in at least three senses of the term “metaphysics.”
First, it is a theory which claims that absolutely everything shares a set of features: absolutely everything which (really) exists is supposed to be material-energetic and governed by the laws of nature. Metaphysics is the discipline that deals with absolutely everything. It is the most universal investigation into the nature of reality, its composition, and architecture. The claim that metaphysics is ultimately futuristic unified physics can be called “physicalism” or, rather, “meta-physicalism,” as it is based on a metaphysical interpretation of the nature of physics rather than on physics, as it happens to be.19
Second, materialism is not an empirical claim. Empirical claims are claims about the composition of specific regions of the universe. We often generalize inductively or in some other legitimate way on the basis of given data, but it is the nature of data – that is, information – that it is always limited. Here is a simple illustration of the contrast between metaphysical and empirical that I have in mind: it is an empirical fact that there are both bosons and fermions. We managed to discover this in a certain way and we have good reasons to ascribe different properties to these particles, which is why we believe that they are different. Knowing something about bosons means acquiring information, which puts us in a position to distinguish one (kind of) physical object from another (kind of) physical object. This is empirical knowledge based on information that we use in order to build a theory, which allows us to understand the basic structure of some phenomenon or other. In contrast to this empirical knowledge, to know that all physical objects are objects, or to know that every physical object is identical with itself and differs from other objects, is categorically distinct and relegates us to a different level of generality. It is hard to see what it would mean to refrain from such a knowledge claim or to base it on privileged cases (or any case at all). It carries almost no information and certainly on this level of abstraction carries no information that helps us to distinguish some natural object from any other natural object.
Materialism makes claims about all objects. In this respect, it cannot tell us anything about those objects except that they differ from other kinds of object, which according to materialism do not exist. The objects whose existence materialism rules out are the immaterial objects. Material objects do not differ from immaterial objects because they have different properties. The point of materialism is a denial of the very existence of immaterial objects. If they do not even exist, they cannot have any properties by which they can be distinguished from material objects. The materialist is not an open-minded researcher who is willing to countenance the existence of immaterial objects if someone can point them out to her, for it is extremely straightforward to do this without changing the materialist’s mind. There are numbers, republics, fictional characters populating novels, movies and dreams, color sensations and beliefs, none of which are evidently material-energetic physical objects. The materialist is not moved by my insistence that there are these objects, but will immediately look out for a theory construction that allows her to eliminate these objects from a scientifically minded world-view by claiming that they have a hidden material nature. From this theoretical attitude alone, you can immediately tell that materialism is a metaphysical and not an empirical view based on actual scientific discoveries. It is in principle impossible to empirically discover the alleged fact that materialism is true, as no actual empirical discovery rules out the existence of immaterial objects.
Third, materialism is also a metaphysical thesis in that it claims to explain reality as it would have been had no one ever noticed that it is a certain way. Materialism is supposed to be a strictly theory-independent fact – that is, a fact we discover but not one we produce by having a belief to the effect that it is true. We do not make materialism true by believing that everything is material. It is supposed to be an insight into the nature of reality, one with the somewhat special status of both drawing on actual scientific knowledge and going beyond anything that could be either empirically tested or refuted.
Let me give you a straightforward example of the tensions this creates. Daniel Dennett, who leaves no room for doubt about his materialist credence, claims early on in his Consciousness Explained: “In short, the mind is the brain. According to the materialists, we can (in principle!) account for every mental phenomenon using the same physical principles, laws, and raw materials that suffice to explain radioactivity, continental drift, photosynthesis, reproduction, nutrition, and growth” (Dennett 1991: 33). Now, notice the suspicious exclamation mark in the quote, which at first glance seems to be an avowal of modesty. Yet, it really amounts to the stance Karl Popper labeled “promissory materialism” (Popper and Eccles 1977: 205), as the possibility of accounting for mental phenomena from a materialist standpoint is as yet far from realized.
Remarkably, less than thirty pages before this quote, in the opening argument of the entire game, Dennett argues against the anti-materialist strands of philosophy of mind on the basis of a rejection of possibilities in principle:
One should be leery of these possibilities in principle. It is also possible in principle to build a stainless-steel ladder to the moon, and to write out, in alphabetical order, all intelligible English conversations consisting of less than a thousand words. But neither of these are remotely possible in fact and sometimes an impossibility in fact is theoretically more interesting than a possibility in principle. (Dennett 1991: 4)
I concur! However, the lesson to draw from this is that it is impossible in fact to establish the truth of materialism on the basis of what we actually know from the natural sciences. What is worse for Dennett is that within thirty pages we witness a straightforward methodological contradiction: on the one hand, our construction of a theory of consciousness is supposed to rely on an empirical spirit as opposed to “these possibilities in principle,” while, on the other, that empirical stance itself is only delineated in virtue of a “possibility in principle.”
So far, I have argued that metaphysical naturalism – that is, materialism – fails because it is a methodological mixture of metaphysics and empirica
l research. It is simply a largely unwarranted pseudo-inductive overgeneralization.
There is a second set of prominent anti-materialist arguments in contemporary philosophy. Arguments in this second set derive from the exciting interface of philosophy of mind and philosophy of language. Standard philosophy of mind deals with the mind–brain problem – that is, with the problem that it is very hard to see how mental items could be related to physical items and processes that fit into the natural order, such as the biochemical processes that take place within certain regions inside our skulls. Yet, one might wonder how we can actually flesh out what is so worrisome about the mind–brain problem (if there actually really is such a problem). One overall answer to this question draws on the conceptual machinery of the philosophical theory of meaning, more specifically on truth-conditional semantics. Roughly, truth-conditional semantics studies the relation between fragments of language and what they are about – between word and world, to put it in words of one syllable. In this context, one can approach the mind–brain problem via the following basic reconstruction of the conceptual machinery that creates the air of paradox constitutive of the mind–brain problem.
Neo-Existentialism Page 3