The Epistemology of Microphysics

Summary

The Epistemology of Microphysics Edward Feser [A lecture delivered at the 49th Annual Meeting of the American Maritain Association at Loyola Marymount University, Los Angeles, CA on March 21, 2026] Microphysics is the branch of physics that studies molecules, atoms, and elementary particles. Two facts about it are especially noteworthy from the point of view of the theory of knowledge. The first is the astounding amount we have come to learn about this part of reality, despite our having no direct perceptual access to it. The second is that progress has slowed considerably in recent decades, at least in the opinion of many physicists. Among these is Sabine Hossenfelder, who argues that the source of the problem is that contemporary research in fundamental physics is dominated by mathematical constructs that are nearly impossible to test empirically and embraced instead for largely aesthetic reasons.[1] Similar criticisms have been raised by Roger Penrose, Lee Smolin, Peter Woit and others.[2] What I will argue is that both the success and the frustrations of microphysics have common epistemological roots, which Thomistic philosophical considerations help to expose and illuminate. While these considerations are not inherently theological, they have implications for theology just as they do for physics. And it will turn out that the scope and limits of what we can know where the micro-world is concerned parallel the scope and limits of what Thomism says we can know by reason alone about the existence and nature of God. In both cases, the human intellect can press well beyond what the senses alone could reveal, but only so far. And in both cases, the intellect’s powers give out as it approaches one end or the other of the ontological spectrum – the divine essence being at the top of that spectrum, and what Thomists call prime matter at the bottom. From atomos to strings The place to begin is with a brief overview of how physics has come to know what it knows about the ...