Does philosophy still have a role in telling us about the fundamental nature of reality?

“Philosophy is dead.”

This is the provocative judgement of professor Stephen Hawking, presenting at a conference in May 2011. He has written elsewhere, “How does the universe behave? What is the nature of reality?… Traditionally these are questions for philosophy [but] philosophy has not kept up with modern developments in science, particularly physics.” Was the world’s most prominent physicist right? To begin with, Hawking’s pronouncement can’t possibly be an indictment of fields like ethics, aesthetics or political philosophy- he is most likely referring to a perceived failure of metaphysics and the philosophy of science. Hawking’s misgivings are understandable. To begin with, physics has made enormous progress in a comparatively brief period; today, the vast majority of physical phenomena can be observed, predicted and explained in terms of an appropriate model or theory. On the other hand, a broad survey of the history of metaphysics gives the impression of a discipline receding in conjunction with physics’ rapid advancements. Take for instance Aristotle’s Physics, which dominated physical descriptions of the world until the discoveries of Galileo and later, but more significantly, Newton. In one perspective, physics’ great advantage was its empirical foundations- theories were built upon detailed observations and lead to concrete predications, while the philosophy exemplified by Physics embodies a speculative, ‘blindfolded’ species of empirical enquiry- the foetal stage of physics. If we take this naïve view, then I would readily agree with Hawking. However, this type of philosophy is largely a historical artefact: from the scientific revolution, to Kant’s Critique of Pure Reason, metaphysics without empirical experimentation has steadily declined in relevance. What, therefore, might be the task of philosophy in describing reality?

Creativity and Revolutions

To begin with, philosophy serves a valuable psychological function in theoretical physics. We are presented with an image of physics as a steadily progressing corpus of knowledge, relying on a dependable ‘scientific method’ of empirical observation, hypothesis-making, and subsequent refinement. Thomas Kuhn showed that this model of physics is incomplete- in reality, the history of physics is a story of steady progress followed by dramatic ‘paradigm shifts’, where a paradigm is the system of assumptions in which physical theories are framed. “Without commitment to a paradigm” says Kuhn, “there can be no science.” Nevertheless, a scientific paradigm is by its definition non-empirical, which leads to an important point: if Kuhn is right, there is no ‘objective’ or ‘worldview neutral’ physics- in order to be a physicist you are required to adopt a paradigm. This is often carried out with no awareness- yet as Daniel Dennett observes: “There is no such thing as philosophy-free science; there is only science whose philosophical baggage is taken on board without examination.”

Thomas Kuhn

A ‘revolution’ takes place when a new paradigm is adopted. My contention is that philosophy is an invaluable tool for precipitating scientific revolutions in this Kuhnian sense. We have determined that paradigms are not determined by observation- they interpret and locate observations within a model. Therefore, revolutions in our understanding of the nature of reality require original thought of the sort that philosophy is best placed to deliver. The inquisitive open-mindedness of philosophy (as a mode of thought as opposed to a body of thought) provides a catalyst for such creativity. It is therefore no coincidence that perhaps the three most significant revolutions in our understanding of the universe came from avid readers of philosophy: Newton wrote almost as much philosophy as physics, while Einstein read Schopenhauer, Kant and Leibniz. He wrote “A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is — in my opinion — the mark of distinction between a mere artisan or specialist and a real seeker after truth.” Finally, Werner Heisenberg, who received the 1932 Nobel Prize in Physics “for the creation of quantum mechanics”, similarly extolled the virtues of philosophy. Indeed, in Physics and Philosophy he shows how it is philosophy, working on the findings of quantum theory, that tells us about the nature of reality. It is this role of philosophy as an interpreter of physics that may tell us the most about the nature of reality. Let’s take quantum physics as perhaps the most significant attempt to uncover the nature of reality. The world of the extremely small appears to behave in a way that is, on the face of it, fundamentally indeterministic and shockingly counter-intuitive. To give a few examples, the smallest constituents of matter can be described in terms not only of being a ‘particle’, but also of a ‘wave’- while no concept adequately explains observable phenomena on its own. Heisenberg’s uncertainty principle tells us that some properties of particles are fundamentally unknowable- and particles can even be said to occupy more than one position at once! Physicists have devised mathematical formulae which can predict and explain quantum behaviour very effectively. However, the meaning of quantum physics is not determined by the mathematics, nor the observations alone. That is to say, the way we interpret strange quantum observations and the formulae that describe them is not implicit at all. There remain questions which cannot easily be settled upon by physics alone, such as: “What is the meaning of chance in the quantum world”, “What is the role of causation at the quantum level?”, and “According to quantum physics, what is real?” There is no consensus here precisely because these questions do not appear to be empirically determinable. However, here is a series of questions concerning the nature of reality that feature terms deeply familiar to metaphysics: terms like “causation”, “chance”, and “real” are woven into the philosophical tradition.

Philosophy and Physics in the 21st Century

Roughly a century has passed since the initial development of quantum theory, and still no consensus on how we might interpret it has emerged. Moreover, the two main theories that in conjunction describe the universe: general relativity and quantum theory, have not yet been reconciled into one ‘grand unified theory’, despite decades of effort. One reason for this may be the increasing scarcity of empirical data- enormous amounts of energy are now required to uncover novel observations. Regardless, theoretical physics has reached a severe impasse- questions are being raised over the nature of time, space and causation, with scarce data to differentiate between competing arguments. As I have claimed, this is an apt opportunity for philosophy to contribute to such debates. There are two separate roles for philosophy to play here: a metaphysical one: interpreting theories from physics to make claims about the nature of reality, but also a more modest one: clarifying terms and elucidating meaning- a useful, Wittgenstein task, since we are told “a philosophical work consists essentially of elucidations”.

Consciousness

There is a further problem concerning the nature of the reality that exists beyond the domain of physics: consciousness. How and why is it that a rich inner life- with subjectivity, semantics and intentionality, arises from physical processes? It seems completely unreasonable, but the fact of consciousness is the most immediate and obvious fact any of us have access to. This is the ‘hard problem of consciousness’, and it remains a point of philosophical discussion. Some philosophers seek to reduce conscious experience, or qualia, to material constituents. For others, consciousness plays a role in the nature of reality itself. Such theories, such as ‘panpsychism’ or ‘neutral monism’, ascribe an irreducibly mental quality to the basic constituents of reality. Whatever the correct explanation might be, it is important to note that here we have a discussion of the very nature of reality where physics is not only lacking guidance, but is altogether uninvolved: it is a task almost entirely resolved for philosophy to settle the issue of consciousness. To conclude, we have seen why Hawking was wrong- philosophy is useful as a psychological tool, as a means of elucidating ambiguous terms, as means of interpreting results in theoretical physics, and in settling problems like consciousness where physics has no stake. However, philosophy and physics appear to have drifted apart. Carlo Rovelli, a theoretical physicist and philosopher of science, claims that while “the great physicists of the first half of the twentieth century loved philosophy” in the latter half “came this fracture between physics and philosophy”. In addition, Gian Giudice, head of the Theory Department at CERN, has said “we are struggling to find clear indications that can point us in the right direction. Some people see in this state of crisis a source of frustration. I see a source of excitement because new ideas have always thrived in moments of crisis.” Perhaps, therefore, philosophy is needed more than ever in the quest to describe the fundamental nature of reality.