The modern versus the Neo-Aristotelian conception of scientific laws

The standard view of laws of nature regards them as universal regularities, ordered in something like a pyramidal structure, and where at least the laws at the apex of the pyramid are ontologically fundamental in the sense that they don’t presuppose anything else (except God, for proponents of the standard view who are theists). They are universal in the sense that they hold everywhere and always. … When we reach the laws at the top of the pyramid, we have (if you’ll pardon the mixed metaphor) reached metaphysical bedrock. (For the atheist, anyway. Again, the theist who is committed to this picture of laws would say that God is the cause of the laws. Even for such theists, though, there is nothing in the natural world that is more basic than the laws.) (Edward Feser, Aristotle's Revenge, p. 177)

There is another way to understand laws of nature, however, which is most famously associated with Nancy Cartwright and first set out in the essay collected in her influential book How the Laws of Physics Lie (1983). On Cartwright’s view, each of the tenets of the standard view is false. First, laws are not universal regularities. Or to be more precise, if interpreted as universal regularities, laws turn out not to be strictly true; whereas if they are interpreted in a way that makes them come out true, they are no longer strictly universal. … Laws are true only ceteris paribus, only when certain conditions obtain. In that case though, they correctly describe the behavior of the entities they govern only under those particular conditions, and are not true of the entities universally. (p. 178)

A second way Cartwright departs from the standard view is by denying that laws are ontologically fundamental. What are fundamental to the entities studied by physics and the other sciences are rather their natures and capacities (Cartwright 1999, pp. 59-73, 78-90). By virtue of these natures and capacities, entities “try” or “tent” to behave in certain distinctive ways (1999, pp. 28-29), and the tendencies of one entity can combine with those of another to produce a joint effect. (p. 178)

Such an arrangement constitutes what Cartwright calls a “nomological machine” (1999, chapter 3). Laws are essentially descriptions of the regularities characteristic of a certain kind of nomological machine. … (p. 179)

The third way Cartwright’s position differs from the standard view is that she takes laws to form a “patchwork” rather than a pyramid (1999, chapter 1). There are the laws describing the behavior of this nomological machine and the laws describing the behavior of that one, but we have no reason to believe that anything unites them all. In particular, we have no reason to believe that laws are arranged in a hierarchy or that there is some one most basic law or set of laws from which all the others follow. (p. 179)

… there is nothing in the actual findings of modern science that favors the standard view over hers. Empirically speaking, the rival views are evenly matched at best, with the choice between them essentially philosophical rather than scientific. (p. 179)

As an alternative to the "mechanical" view of science and the world, Edward Feser sets forth an alternative vision whereby science is merely descriptive of systems not of things. Things rather are as Aristotle sees them, as things with their own natures and capacities, borrowing from Nancy Cartwright's view, and thus things rather than laws are fundamental. Lastly, laws are disparate not connected together, since they are not fundamental for reality but merely descriptive of systems. Feser further asserts that the difference between these two models of reality are empirically indistinguishable, and therefore science does not and cannot disprove his alternate ontology.

On a surface level, the two models seem indistinguishable. However, I would assert that it can be proven that Feser's alternate model is unable to justify science and the workings of science, and I would do so by looking at each of the three Cartwright tenets that Feser embraces.

The first tenet is a rejection of the universality of scientific laws. Feser asserts universality to be false because things in real life do not follow scientific laws, as the laws only apply in ideal situations which are not found in this life. In a sense, it is true that there the real is different from the ideal, but it is a leap of logic to assert that therefore laws are not universal. The fact of the matter is that under certain situations, we can approximate the ideal. For example, under high temperature and low pressure situations, all gases approximate the Ideal Gas Law, regardless of whether it is chlorine, argon, or carbon dioxide gas. In chemistry, the stochiometric ratio of the reaction of sulfuric acid with sodium hydroxide is always 1:2, and this applies to the reaction of any diprotic base with a monoacidic base. Newton's First Law can be easily proved in space where friction is negligible if not absent. In other words, the distinction between the real and the ideal does not in any way invalidate the application of scientific laws.

But, Feser will object, that only proves that the laws work only under certain conditions, does it not? No, for the beauty of science is that in non-ideal scenarios, the other variables can be factored into the equation and applied then. For example, the Van der Waal equation with variables a and b work for real gases. In mechanics, the force of friction can be measured and taken into account. In chemistry, impurities in chemicals can be ascertained and factored into chemical reactions. In other words, scientific laws do not apply only under "certain conditions." The simple form of the law can be seen only under ideal conditions, but the laws do apply under all conditions.

Compounding the problem with Cartwright's first tenet, a rejection of the universality of laws breaks the practice of science. If laws are not universal but particular, then science and technology would grind to a halt. Why should anyone think that the application of a certain temperature in an industrial plant would result in fractional distillation of petroleum? Rather, if universality is rejected, each industrial application must be investigated anew since what works for one "substance" (e.g. alcohol and water) may not work for another "substance" (i.e. petroleum). We cannot assume that gravity on other planets would necessarily follow either Newton's Law of Gravitational Attraction or Einstein's General Theory of Relativity either. Therefore, while Cartwright's first tenet cannot be disproved empirically, it vitiates the practice of science altogether. For science to be science, laws must be both universal and true.

Cartwright's second tenet places things as being fundamental not laws. The problem with this new take on Aristotle is that it can be proven that laws are more fundamental than things. The ability to transform one element to another through radioactive decay, through bombarding things with energetic particles (e.g neutrons, alpha particles, other atomic nuclei), or through nuclear fission and fusion, have proven that atoms are in fact real and fundamental and that Aristotelian "substances" are at best an emergent quality. The creation of anti-matter, and the ability to destroy matter by combining that matter with anti-matter to form pure energy, are not hypotheses but actual experimental science. On this second tenet therefore, science has indeed disproved Cartwright's new take on Aristotle.

On Cartwright's third tenet, that is debatable. Scientists have not yet discovered a unifying theory of everything, and it is uncertain if they ever will. However, the problem with the third tenet is not that there are certain disparate sets of laws, but rather Cartwright's denial of all hierarchy goes against our understanding of how the various scientific disciplines connect to each other.

The convergence of scientific disciplines (and here I focus only on the natural sciences) is seen in for example biochemistry, whereby biology and chemistry are integrated. The biochemical pathway of glycolysis for example show how chemistry underlies biological nutrition, and thus chemistry is more fundamental than biology. When one looks into molecular structure in bond length, angles of chemical bonds, valence electrons and dipole movement, it can be seen that physics is more fundamental than chemistry. All of these prove that there is some hierarchy among scientific disciplines and scientific laws. Along with the rejection of second tenet, the scientific picture of atoms and laws of nature appears more credible than the Neo-Aristotelian version of substances being fundamental. A deeper understanding of science here thus falsifies Cartwright's third tenet.

As it can be seen, on the surface, it seems that Cartwright's and Feser's model of ontology and science is empirically indistinguishable from the modern ("mechanist") model. But a deeper understanding of science falsifies that model. One can reinterpret certain scientific laws in line with this Neo-Aristotelian model, but the model cannot and does not work for actual scientific practice and understanding. Cartwright's and Feser's model of science and scientific laws are therefore to be rejected as contrary to how science actually works.