I have been preparing for a conference on Consilience that will be held at the University of Missouri-St. Louis on April 26-28, while at the same time — and for entirely independent reasons — I have been reading and discussing with some graduate students a book by James Ladyman and Don Ross, Everything Must Go: Metaphysics Naturalized.
The conference will be a discussion of E.O. Wilson’s idea of consilience as the unity of knowledge, and Wilson will be opening the proceedings. Looking at the fields of interest and the names of most of the other speakers, I suspect I will be the token skeptic there. Wilson has (mis-) appropriated the word consilience — which was coined by philosopher William Whewell in the 19th century to indicate a particular type of inductive reasoning (known also as inference to the best explanation, or “abduction”) — to advance his own notions of reduction of the humanities to science, and particularly to biology. I think Wilson was way off the mark on this, and I’ll explain why at the conference (I will post my presentation for download soon over at my professional site). Meanwhile, look at this devastating review of the original book by evolutionary biologist Allen Orr.
Ladyman and Ross’s book is a highly technical take down of much of what goes on in the field of metaphysics these days, where the authors start from the (very reasonable, I think) point that any respectable metaphysics ought to take seriously the latest news from physics (a position apparently shared by only a minority of metaphysicians). The book goes on to propose a particular version of a philosophy of science position known as structural realism, according to which scientific theories neither track objective reality in a straightforward sense (the so-called realist position), nor do they simply provide us with theoretical conceptions that “work” but whose closeness to truth cannot be assessed (the so-called anti-realist position). Rather, structural realism posits that when scientists abandon one theory for another one (say, Newtonian mechanics in favor of General Relativity) what is retained in the new theory from the old one is a set of mathematical relationships (describing the underlying “structure” of reality).
I don’t want to get into the details of this particular debate in philosophy of science — which is very interesting but also gets highly technical pretty quickly — but rather point out the similarity between Ladyman and Ross’s attitude and that of Wilson, as well as that of other people whom I more than occasionally criticize here (the list includes, naturally, Jerry Coyne, Sam Harris, and Alex Rosenberg, all for slightly different but related reasons). That similarity consists in a type of stance (as philosophers say) that I am going to dub “fundamentalist reductionism.” Let me elaborate. [Full disclosure: James Ladyman is a contributor to a book I have been editing for Chicago Press, on the philosophy of pseudoscience, and I have repeatedly used his excellent textbook on philosophy of science for my classes.]
One of the crucial arguments Ladyman and Ross advance in defense of their version of structural realism is that, at bottom, modern physics tells us that there are no things, just structures (or, to be more precise, that structures are ontologically prior to what we call things). They interpret modern quantum mechanics — particularly because of concepts like quantum entanglement — as telling us that individual objects, including you and me, planets, galaxies and so on, do not reflect the fundamental structure of the universe. Indeed, that when we get to the foundations of it all, not even sub-atomic particles are real in the sense of which most people understand that word. The foundation of life, the universe and everything is made of structures that describe phenomena (even causality goes out of the window, ultimately). At some point Ladyman and Ross admit that their position is compatible with some version of mathematical Platonism, though they stop shy of a full endorsement of that view. (I’m actually somewhat sympathetic to mathematical Platonism, but that’s another story.)
Let us assume for the sake of argument that the latest 21st century physics really is best interpreted the way Ladyman and Ross do interpret it: at the bottom of the fabric of reality there are structures that can be described mathematically, and that these structures are somehow prior to the things that we normally count as constituting the universe. It does not seem to follow from this that the existence of individual objects is thereby an “illusion” (and hence, that any type of metaphysics that talks about the properties of individual objects is nonsense). To reach that conclusion one must take the additional step of assuming a form of greedy reductionism, where the lowest level is the only one that matters, everything above it being somehow illusory or misleading. That position is what I take to be an instance of fundamentalist reductionism. (Other partial examples include Harris’ and Coyne’s claim that consciousness is an illusion; Rosenberg’s repeated assertions that pretty much everything is an illusion; and Wilson’s more modest claim that biology is sufficient for an account of all things human — though one would really want to ask Wilson why he stopped at biology: shouldn’t quantum mechanics suffice?)
Now, Ladyman and Ross are more sophisticated thinkers than most of the bunch I have been criticizing, and they do realize that their position faces an obvious problem: if all is (mathematical) structure, then how do we explain the existence of “apparently” individual objects like you and me, planets and galaxies? They say that any good fundamental physics, as well as any good naturalistic metaphysics, has to somehow “recover” micro-, meso- and macro-cosmic realities from whatever nano-cosmic level it takes off from. One of the best known of these attempts at “recovery” is the claim that quantum mechanical effects rarely bubble up to higher levels of complexity because of the collapse of the wave function (which, Ladyman and Ross point out, is a probabilistic-mathematical construct, not a physical “thing”). Okay, but I think it is fair to expect a bit more than quasi-magical words in order to bridge not just QM and classical physics, but also physics with biology, and eventually biology with the social sciences (the latter two being Wilson’s projects, of course).
More to the point, I don’t think it makes much sense to claim that higher level objects do not “really” exist just because their lower level nature is different. Imagine a biologist who said that ecosystems don’t “really” exist because living organisms are actually made up of cells. Yes, they are, but there are emergent properties (*) and interactions that make it impossible to understand ecosystems as a function of cell structure, and any serious ecologist better acknowledge that and get down to work. Similarly, above-fundamental levels objects are not illusions or a metaphysical afterthought, they are just as much part of reality as the mathematical structures inherent in string theory or loop quantum gravity.
Lee Smolin (whose The Trouble with Physics is an excellent critical take on string theory and the state of contemporary physics) is approvingly cited by Ladyman and Ross as saying “The universe is made of processes, not things.” But that is a categorial mistake. The universe is most definitely made of both processes and things, and the task of physics (and metaphysics) isn’t to tell us to forget about things because the processes may be ontologically prior. It is to tell us what it means for processes to have that function, and how do we get the very real things that these processes produce and connect to each other. How do we get, for instance, individual beings, planets and galaxies out of an underlying non-local mathematical structure? Accordingly, a comprehensive metaphysics and philosophy of science cannot be achieved simply by taking what physicists tell us about the fine structure of reality and be happy with some vague handwaving to the effect that the rest of it can be “recovered.” Objects and individuals are here to stay, regardless of whether they are the product of smaller objects or of mathematical relationships.
* I am agnostic about whether emergent properties are such epistemically or ontologically. That is, I do not know — nobody does, really — whether emergent behaviors are such in the sense that they could in principle be derived from complete knowledge of fundamental states or whether there really are properties that come into being only under certain conditions of complexity. The point is, emergent properties, even in the weak epistemic form, exist, and serious science and metaphysics simply cannot brush them aside.