Philosophers of science on which theories are fundamental

What is real? What is true? These big questions are central to philosophy and issues in the philosophy of science.

Emergent properties of complex systems raise similar philosophical questions such as  "What is fundamental?" and "Are quasiparticles real?".

Robert Batterman is a philosopher of science who is the author of the book,

The Devil in the Details: Asymptotic Reasoning in Explanation, Reduction, and Emergence

In 2017 Batterman wrote an article in an edition of the Journal of Statitiscal Physics that was in memory of Leo Kadanoff. 

Philosophical Implications of Kadanoff’s Work on the Renormalization Group

Below I reproduce some of the text as it provides a helpful (and disturbing) summary of how the philosophy of science has evolved.

There are very few natural philosophers anymore. The fields of philosophy and science parted company at the end of [the nineteenth] century. Philosophers more and more began to turn toward the disciplines of logic and the analysis of language, and their examination of the enterprise of science began to follow a different, less-engaged-with-scientific-detail, direction. They began to try to determine the logic and structure of scientific theorizing in a way that was much more arm-chair and much less concerned with details about individual theories. The aim was to construct or reconstruct the proper logical structures of scientific explanation, confirmation, and theory choice. The philosophical reconstructions were, by and large, designed to fit all empirical science. For example, an explanation in physics should share the same general (logical) form as explanations in biology, chemistry, or sociology. 

I find this problematic because how physicists and biologists do science and the knowledge that they produce is quite different. In fact, similar differences exist between elementary particle physics and condensed matter physics. That also applies to Batterman's next claim.

I think it is fair to say that from a philosophy of science point of view, physical theories are supposed to reflect our best attempts to understand nature. Philosophers are also enamored with the idea that theories have a certain logical structure—they can be written down in some kind of axiomatic form from which, given certain inputs, various features of physical systems (future states, e.g.) can be derived using logic and reasonably straightforward mathematics.

Furthermore, philosophers often distinguish fundamental from nonfundamental (or “phenomenological”) theories. This latter distinction presupposes the idea that fundamental theories are the ones that tell us really what nature is actually like at “bottom.” These presumably include, quantum theory, quantum field theory, maybe a theory of quantum gravity, etc.

In contrast, Bob Laughlin, argues that certain emergent properties are exact [such as quantisation of magnetic flux in a superconductor, hydrodynamics, sound waves] and so they are more fundamental than microscopic theories. [A Different Universe, pp. 36-40].

Batterman continues

Nonfundamental theories such as thermodynamics, continuum mechanics, and fluid dynamics, on the other hand, while pragmatically useful, are in a certain sense (exactly what sense is a matter of serious contention) superfluous. We could, in principle, solve problems involving the elastic bending of beams by starting from the fundamental atomic and subatomic theories of the constituents of the beam.

Nonfundamental theories don’t get nature right. Steel beams are not really the continua whose bending behaviors are described by the Navier–Cauchy equations. Gases are not continuous blobs of stuff. The important theories, according to many philosophers and, I believe, according to many physicists, are those that get the ontology right. In part, the (often unarticulated) reason for preferring fundamental theories over phenomenological theories is a realist presupposition that physical theories must accurately describe the world the way the world really is. 

 Perhaps the view that atoms are real but solids are not is reflected by Bertrand Russell in the opening paragraph of his book, The ABC of Atoms, published in 1923 and intended for popular audiences.

Phenomenological theories are often good for calculating, but they don’t accurately describe the world and so must, in a sense, play second fiddle to their fundamental partners.

This is also contentious. Thermodynamics, elasticity theory, and fluid dynamics are perfectly accurate and never wrong within their domain of validity. Many courses and texts on thermodynamics begin with the following quote from Einstein.

 A theory is the more impressive the greater the simplicity of its premises, the more different kinds of things it relates, and the more extended its area of applicability. Therefore the deep impression that classical thermodynamics made upon me. It is the only physical theory of universal content which I am convinced will never be overthrown, within the framework of applicability of its basic concepts.

I should stress that Batterman is not agreeing with or promoting the views I have questioned above. Rather, he is trying to characterise what many philosophers believe.