Monday, December 20, 2010

Stephen Barr on science and metaphysics

Stephen Barr, The Symbiosis of Science and Metaphysics (via Joe Carter).

The arrogance of scientists lecturing to philosophers on how they should do philosophy? That is what I thoght at first, especially when Naturally, John Farrell expressed his appreciation at First Things, especially of the closing:
In short, Aristotelian/Thomistic philosophy has paid a heavy price for the two and a half centuries in which it largely ignored what was going on in the natural sciences. A sustained re-engagement with science would enrich its conceptual and linguistic resources. This re-engagement cannot simply be an attempt to translate statements of modern science into existing Aristotelian terms. That cannot be done in many cases. Rather, many more Aristotelian/ Thomistic metaphysicians than currently do must learn to listen to and understand science in its own native tongue.
But then I went ahead and read the rest of the essay.
Beyond directly theological issues, does modern physics have anything to say to metaphysics, and therefore indirectly to theology? Some might argue not, on the grounds that metaphysics speaks about such general features of reality - of being as being - that it cannot be affected by discoveries of particular contingent facts about the world. And yet, Aristotelian metaphysics, which has such an important place in Catholic thought, was not conceived in isolation from scientific investigation. Aristotle was himself a great scientist and both his metaphysics and science make use of the same technical apparatus of form, matter, substance, accident, potency, act, and so on. Indeed, it was largely as a theory of nature that Aristotelianism first commended itself to medieval Christian thinkers.

It is a great problem that traditional Aristotelian/Thomistic metaphysics and modern science no longer speak the same language, as they did in the Middle Ages. Indeed, there are many terms and concepts in the language of each that are now almost untranslatable into the language of the other. Some argue that this is the fault of modern science, which restricted its attention to a limited range of questions having to do with the merely quantitative aspects of things and with efficient and material causes at the expense of formal and final causes. While there is some truth in this, it is only a part of the story. The language of Aristotelian/Thomistic metaphysics has changed very little since the advent of modern science and its vocabulary seems from a scientific perspective quite stilted and awkward for many purposes.

Physics has had enormous success in explaining why things happen as they do in the natural world, but its modes of explanation do not fit neatly into the four-fold classification of material, formal, efficient, and final causes. For example, when physicists explain the electrical conductivity of metals in terms of the "band structure" of the energy levels of the electrons in a crystal lattice of atoms, to which of the four causes does that correspond? As this example illustrates, explanation in modern physics is almost entirely in terms of mathematical structure and involves an enormously rich set of ideas about form. The fact that modern science is nonetheless typically accused by Aristotelian/Thomistic metaphysicians of neglecting "formal cause" shows that they are working with a different notion of form than are contemporary physicists and mathematicians. In Aristotelian/Thomistic philosophy, the ideas of formal causation and substantial form have a teleological thrust that is largely missing from the physicist's conception of form, which corresponds more to Lonergan's broader idea of form as "intelligible structure".

Another example of a linguistic/conceptual difference between Aristotelian thought and modern science is that the former usually envisions the action of one thing upon another (for example fire heating iron), whereas in modern physics the physical world is explained in terms of mutual "interactions". A third example is that the notions of "species" in Aristotelian philosophy and modern biology are not compatible. Aristotelian species are what mathematicians call "equivalence classes", so that if A is of the same species as B, and B is of the same species as C, then A must be of the same species as C. However, it does not appear possible in biology to define species in a way that always satisfies this condition. (The existence of "ring species", such as the Larus gulls, illustrates the problem, as indeed does "speciation" in evolution, whereby all animals are of the same species as their parents and offspring, but not as their remote ancestors or descendents.)

He makes some good point about Aristotle being a "scientist" and a "philosopher." But the rest...

Even if they are well-meaning, Catholic scientists who would seek to advance the credibility of the Church and the Catholic intellectual tradition should instead examine their starting points and assumptions, and check their reasoning. Those philosophers and theologians who would seek to have discussions with such scientists (as the River Forest School used to promote) should always check the logic (especially the definitions of terms).

Even now we still have some Dominicans of the River Forest School continuing the work of the school: Fr. William Wallace, especially. And then there is Anthony Rizzi, who was apparently influenced more by Maritain. Aristotelian-Thomists have no problems reviewing contemporary scientific literature -- what will irritate the Catholic scientists is when they do so critically. Philosophers and theologians of other schools may be more deficient in their training, so I would not suggest that they grapple with the literature right away--rather they should study logic, physics, and philosophy/history of science. Talking about the "mode of explanation" of Aristotelian physics shows that Barr has not gone far enough in a critical examination of what he believes. One does not evaluate what some philosophers have written with belief -- one must start off first by asking whether one has belief or true knowledge, and only then can one critique what others have said.

Aristotelian-Thomistic vocabulary begins with what we first know and it is used to understand what we come to know. We do not go in reverse, attempting to understand what is better-known through what is less-known, which is what contemporary scientists would have us do. If modern science is criticized as neglecting the formal cause, it is conjunction with critiques about its mathematical character and reductionism.

Barr concedes that physics almost entirely in terms of mathematical structure, and yet "involves an enormously rich set of ideas about form," using the example of electronic band structure, Claiming that is so does not make it so. What he neglects to examine is how one arrives at that mathematical structure in the first place -- quantity and measurement -- from what causal interactions are such measurements derived? Moreover, the avoidance of teleology does not make a causal (i.e. scientific) account of x wrong -- it merely makes it incomplete, and those who would maintain that this is a complete explanation (or the only one attainable) are therefore wrong.

As for species -- James Chastek has written something recently on this question, and I have yet to think about what he says. Is it necessary for an account using a more traditional notion of species ("kinds") to be reconciled with the modern biological notion? No. But that does not mean that it cannot be done, even if one can concede that species refer to populations of individuals that reproduce and are isolated from other populations (Ernst Mayr's definition). Talking about a group and its lineage of reproduction/descent does not exclude the possibility that there are natural limits to the variation of structure within that group/lineage.

Philosophy Lives
Why Stephen Hawking’s attempt to banish natural theology only shows why we need it.
John Haldane


Geremia said...

This thesis is important because, e.g., Heisenberg recognized in his Physics and Philosophy that the probability wave concept in quantum mechanics "was a quantitative version of the concept of 'potentia' in Aristotelian philosophy" (p. 41) and that the "concept of the soul for instance in the philosophy of Thomas Aquinas was more natural and less forced than the Cartesian concept of 'res cogitans,' even if we are convinced that the laws of physics and chemistry are strictly valid in living organisms." (p. 80).

Geremia said...

I think my first comment on this post landed in your SPAM folder again...

papabear said...

I'll republish your first comment in a post to the blog.