Over the past couple years or so, I have conversed with physicists from the level of professor to the level of the undergraduate. Of course, no offense to the latter, but when talking about philosophy – the nature of reality in particular – I never expect much. In fact, nothing much at all is even expected. Most physicists at such a young age entering into the life of the university don’t take too much into account the underlying philosophical work within their discipline. You’ll sometimes find those who are interested in quantum physics occasionally bring up Descartes, but even then their “scientific” pride still evades possibly gaining insight or really having a grip on the conversation Descartes set in motion.
Unfortunately, philosophically lame physicists can even carry over onto the professional level. Sure, this can mean a number of things. To make clear, however, this isn’t to say that a physicist doing some treatment on the nature of a phenomena knows nothing of existential realities or ontology. Usually when I say “philosophically lame” I mean more so a lack of consideration for insight. The physicist in his study of the behavior of heat can say “OK, I can quantify this by such and such method because I know the difference between ‘hot’ and ‘cold’.” However, with something so mysterious as a quantum field, he can no longer have this attitude. To maintain that attitude would be an example of a physicist lacking consideration for insight into the nature of a thing (a philosopher’s area of interest).
The study of being (ontology) wasn’t something too considerable for physicists if it wasn’t for quantum mechanics. Before Einstein’s revolutionary work in gravity and the speed of light, the universe – from the smallest to even the most massive objects – was bound to physical determinism, which is a notion that says that the values of all physically described variables at any one time determines with certainty the values of all physically described variables at any later time. In other words, the universe was mechanistic and followed – and were bound to – certain rules.
René Descartes (1596-1650) believed that nature was divided into two parts: the mental (res cogitans) and the physical (res extensa). The former contains our thoughts, ideas, feelings and so forth, while the latter contains the assignment of mathematical properties to space-time points. Isaac Newton (1642-1727) built upon the ideas of Tycho Brache (astronomical observations) and Johannes Kepler (three laws of planetary motion). Ranging from the laws of gravitational attraction and motion, Newton even extended his ideas down to the domain of the atom. This followed to the idea that the universe (physically described) is bound to physical determinism.
Later, with the introduction of quantum mechanics, humans no longer became the “detached observer” but the fundamental element of interest. Not so much the human itself, but that mind (the mental) entered into quantum mechanics as a basic conceptual structure. It is as Werner Heisenberg wrote: “The conception of the objective reality of the elementary particles has evaporated not into the cloud of some new reality concept, but into the transparent clarity of mathematics that represents no longer the behavior of the particles but our knowledge of this behavior” (Stapp 2009: 18).
What happens when you put all of this together? Hopefully this might help with the explanation of Henry Stapp from the University of California: “The dynamical laws of classical physics are formulated wholly in terms of physically described variables: in terms of the quantities that Descartes identified as elements of ‘res extensa’. Descartes’ complementary psychologically described things, the elements of his ‘res cogitans’, were left completely out: there is, in the causal dynamics of classical physics, no hint of their existence” (Stapp 2009: 17).
The idea that res cogitans were “left out” meant that although we can know these physically described variables, they by no means could affect them in any way. This is what is meant by the “detached observer.” However, with the introduction of quantum mechanics, “[This] revealed an inevitable interaction between observer and observed in the microcosm. Thus, human consciousness entered the realm of physics” (ibid., 89, 90).
This is one way in which Cartesian dualism (in particular) can provide helpful insight into the ontological character of the physical aspect (res extensa) of quantum mechanics. Hence, this is a further example of how physicists can look at the notes of the philosopher.
Quantum Physics of Consciousness. “Quantum Reality and Mind,” Henry Stapp. 2009. ed. Roger Penrose and Subhash Kak.