“As there is a material object behind every sensation, so there is a metaphysical reality behind everything that human experience shows to be real.” – Max Planck, Scientific Autobiography

[Note: I would like to thank Dr. Derek Gardner for reading a draft of this essay and supplying helpful suggestions. His scholarship saved me from making errors when describing quantum mechanics and I deeply appreciate his insight.]

I recently heard a professional philosopher say that metaphysics is no longer a dirty word in the field of philosophy. This was good news to me, because for the last four hundred years or so metaphysics has been considered a lost cause in philosophy. Upon reflection, however, I think there has been a small resurgence in the interest of classical metaphysics but the philosophy of mind, language, science, politics, and ethics still seem to be the most popular areas of study in the field. I’m still told that professional positions for metaphysicians are hard to find. Nonetheless, it is fascinating that philosophy is rediscovering its primary role—to explicate the most universal principles of reality and discover the rules, axioms, and laws that make our universe, fields of learning, and human experience possible in the first place. I think the ultimate questions of reality and what it means to be human will never really go away. Thoughtful individuals will always try to offer systematic attempts to illumine our human experience in depth and set it in a vision of the whole of reality. Why might there be an emerging interest in metaphysics and what would that tell us about the relationship between philosophy and science?

Aristotle explains in his Metaphysics that there is a science (for Aristotle ‘science’ is a body of knowledge) which is concerned with “being as being” and that the primary causes and principles of being are the object of study for the metaphysician. This is the formal study of ontology, the metaphysical exploration of all existing things as they exist, the properties of being, and whether certain things, whose existence can be questioned, do or do not exist. Aristotle also laid out the tactical possibilities for conducting what we now call the physical sciences – the study of the structure and behavior of the natural world through repeated observation and experiment. For Aristotle, however, and the many classical and medieval philosophers that came after him, the physical world and the ultimate principles of reality (what they would have called ‘physic’ and ‘metaphysic’) are not to be divorced or separated because both are needed to explain the ultimate nature and significance of reality. While the subdivision and classification of learning and science is helpful for sharpening one’s focus on their object of study, most areas of study ultimately fall back on basic first principles that attempt to explain or support their overall project, such as the principle of sufficient reason, the law of identity, the law of noncontradiction, correspondence, cause and effect, act and potency among others. Perhaps one reason metaphysics is being re-discovered is that all fields of inquiry, whether the social sciences or physical sciences, use foundational first principles which reflect their basic assumptions about the nature of the universe and how the world works. Note that nearly all our basic assumptions are not empirical in the sense used by Enlightenment philosophers and natural scientists and yet it would be foolish to discard them. There are many immaterial and material aspects of reality. The union of the immaterial with the material has often been discarded or forgotten in Western thought but recently have been rediscovered with interesting metaphysical corollaries. Every cosmology, mathematical formula, scientific hypothesis, and ethical theory has metaphysical implications.

Another reason I think metaphysics is being rediscovered is that a few physicists and mathematicians in the twentieth-century ventured into the discussion and pointed out that physics and metaphysics are indeed related and ought not to be detached. This was a profound change in Western thought at least since the Enlightenment. Due to the skeptical theories of Descartes, Hume, Hobbes, and Kant, metaphysics was considered dead or impossible to pursue. However, interesting scientific developments in the early part of the twentieth-century changed things. Einstein’s colleagues, Max Planck, Werner Heisenberg, G.H. Hardy, Niels Bohr, and Erwin Schrödinger, among others, argued for a new understanding of nature due to the quantum discoveries of their day that described the behavior of reality at the atomic scale, where standard Newtonian physics failed to do so. Here, a basic tenet of quantum mechanics, as opposed to classical mechanics, is that reality, at an atomic level is not causally linear or smooth in its behavior but probabilistically discontinuous and discrete. In Newtonian physics, for instance, and in the classical “every day” large-scale sense to which it applies, it is generally possible to determine the future states of a system by knowing its present state (e.g., we can predict where a baseball will land given some initial conditions). In the new atomic physics of the twentieth century, this was no longer the case. Classical mechanics has at its basis the contention that all states of a considered system can be measured and known. When we describe atomic physics with quantum mechanics, on the contrary, one must accept that it is impossible to know the exact value of a parameter without measuring it, and one can know it only for that measurement. Heisenberg’s discovery of quantum indeterminism suggests that in the moment of an atomic measurement, the system (e.g., a molecule) is necessarily disturbed (e.g., by a probing photon) thus “collapsing” the original potential possibility-space into one state of the many probable states, some with much higher probability, but otherwise without any reason to “collapse” into one or another particular possible state (Silva, 637). The most one can do to describe the state of any given system, before or after the measurement, is to provide a probability for the outcome of that measurement (Dirac, 73).

From the standpoint of Aristotelian philosophy, Werner Heisenberg is especially interesting due to his specific appeal to Aristotelian categories of act and potency when describing his theory of indeterminism. Before getting further into Heisenberg’s interpretation of quantum mechanics, however, it is important to understand the central Aristotelian categories of Act and Potential.

As a quick review, ‘act’ or ‘actuality’ simply refers to that which exists. It is the physical, concrete existence of something (philosophers call this the ‘positive mode of perfection’ but we will not go into that here). For now, think of act or actuality as that which really exists here and now—a physical object. Another way to think of act is that which is ‘informed matter’. (In classical philosophy, matter is not form and form is not matter. Form is the essence of a thing or that which makes something the kind of thing it is and without which it can not be. Ordinarily, essence is considered distinct from existence. This is one reason why all reality has an immaterial as well as material elements.) ‘Potential’ or ‘potency’ is simply all the capacities for change, transformation, or movement that which is in act has. For example, a student has the capacity to become a great mathematician if she uses her rational capacities well. A rubber ball has the capacity or ability to be melted down and formed into a figurine, balloon, or tire. Potential is another way of describing all the possible modes of being something has (it is always innate to that which is in act). Potency is never unlimited, however, and is governed by the essence, nature, or form a thing has—and this will be important when we get to Heisenberg’s understanding of probability and atomic potency. For example, a hamster will never become a helicopter pilot, and a cephalopod will never become an architect because potency only relates to the nature (or essence) of the thing itself. Act and potency are metaphysical co-principles that help us make sense of the world around us. The act/potency distinction is an absolute feature of reality and is accepted by all serious philosophers from the classical tradition through the early modern period, including neo-Platonists and Aristotelians. For example, the neo-Platonist philosopher, Plotinus, appropriated Aristotle’s categories of act and potency when describing change.

Part two will specifically focus on Werner Heisenberg’s book, Physics and Philosophy with some concluding remarks from Max Planck.

Works Cited:

Dirac, Paul. The Principles of Quantum Mechanics. Oxford, Clarendon Press, 1958.

Silva, Ignacio. “Werner Heisenberg and Thomas Aquinas on Natural Indeterminism.” New Blackfriars, 2013, 635 – 653.