Quantum mechanics and the puzzle of subjectivity

Solving Husserl's Crisis of the Sciences

Despite their huge success, the natural sciences have a problem: they don’t seem to leave much room for the human subject. Edmund Husserl thought this was reason enough to declare science was in ‘crisis’! But an influential, though widely misunderstood, interpretation of quantum mechanics by physicists Fritz London and Edmund Bauer, places the subject at the heart of our most successful mathematical physics theory yet, writes Steven French.

 

Husserl’s The Crisis of European Sciences and Transcendental Phenomenology is widely regarded as both his most accessible and most influential work, written under the shadow of fascist ideology looming over Europe. Based on lectures given in 1935 at Charles University and the German University in Prague, Husserl opens by addressing the ‘Crisis? What crisis?’ question that many in the audience must have been asking themselves:

‘I expect that at this place, dedicated as it is to the sciences, the very title of these lectures … will incite controversy.’

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Husserl was alluding to the fact that the German University had been the academic home of such notable scientists as Ernst Mach and Albert Einstein and that science was then enjoying a period of obvious and wide-ranging success. How, then, could he talk of the sciences undergoing a ‘crisis’? Husserl makes it clear that he is not referring to the ‘victorious struggle against the ideal of classical physics’ as represented by the rise of the theory of relativity and quantum physics. Neither is he concerned about the successive rise and fall of one theory after another that historians of science have long pointed to in the face of philosophers’ insistence that science is progressing steadily towards the Truth:

‘Physics, whether represented by a Newton, or a Planck or an Einstein, or whomever else in the future, was always and remains exact science.’

No, the ‘crisis’ that Husserl is referring to here has been precipitated by what he calls the loss of science’s ‘meaning for life’ –  a loss that is embodied in the way that science abstracts ‘from everything subjective’ and clothes the ‘life-world’, that is, ‘the everyday surrounding world of life …in which all of us … consciously have our existence’, with a mathematical ‘garb of ideas’. Here the fall-guy is Galileo, with his talk of the Book of Nature being written in the language of mathematics misleading us into taking as ‘true being’ what is actually only a method, designed to progressively improve our predictions.

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By uncovering this relationship between the subject and the object, at the most fundamental level, and thereby throwing off the ‘garb of ideas’ we can restore science’s original meaning for life.

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Now, Husserl makes it clear that this ‘loss of meaning for life’ does not in any way negate or undermine science’s obvious achievements, whether those include the ‘philosophically revolutionary critique of the ‘classical law of causality’ made by recent atomic physics’, or ‘Einstein’s revolutionary innovations’. Nevertheless, because of this ‘disguise of ideas’ imposed by its mathematization, the true meaning of the scientific method has been obscured and fundamentally misunderstood.

How, then, might this crisis of the sciences be resolved? By the scientist developing ‘…the ability to inquire back into the original meaning of all his [sic] meaning-structures and methods’ which will restore the subjectivity that has been lost. Sadly, however, scientists themselves are ‘normally not at all able to carry out such reflections’ and so the job must fall to the phenomenologically trained philosopher. It is they who, broadly speaking, are equipped with the tools to undertake an investigation into the correlations between our mental acts and experiences, the objects that these acts and experiences are about and the contents or (where appropriate) meanings of these acts and experiences. In other words, it is through a phenomenological inquiry into the original meaning of those acts and experiences that the relationship between consciousness and the world will be revealed. By uncovering this relationship between the subject and the object, at the most fundamental level, and thereby throwing off the ‘garb of ideas’ we can restore science’s original meaning for life. As Dan Zahavi has put it, in slogan form: ‘[N]o object without a subject and no subject without an object’

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The subjectivity that Husserl thought had been obscured by the mathematization of science has in fact been recovered in, and set at the very heart of, that most mathematical of modern theories, quantum mechanics.

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Famously, however, Husserl never completed the Crisis and the manuscript remained unfinished when he died in April 1938. The text ends with him railing against physicalism, insisting that ‘… insofar as the world is a world of knowledge, a world of consciousness, a world with human beings, such an idea is absurd …’. Yet if he had lived just a year or so longer he might have seen the crisis of the sciences resolved by a pair of physicists in their fifty-one page pamphlet on the fundamentals of quantum theory.

This was La Théorie de L’Observation en Mécanique Quantique, published in Paris in 1939 by Fritz London and Edmund Bauer. As a succinct presentation of the measurement process in the quantum context, it has loomed large in the philosophy of physics as explaining the ‘collapse’ of the wave-function when a measurement is made by invoking the observer’s consciousness. Most commentators have interpreted it as little more than a summary of the account presented previously by the famous mathematician and mathematical physicist, John von Neumann. This hinged on the following argument: granted that the ‘cut’ between micro- and macro-systems can only be made in an arbitrary fashion, then if the former can enter into quantum superpositions, so can the latter, and that includes the scientists’ measurement apparatus, their bodies and their brains. Since we never seem to observe superpositions of large objects, something non-physical, such as our consciousness, must cause them to resolve into a definite result when we make a measurement.

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In a famous debate in the early 1960s, between physicist Eugene Wigner and physicist-philosopher Henry Margenau, on the one hand, and, on the other, the philosophers Hilary Putnam and Abner Shimony (who had two PhDs, one in philosophy and the other in physics), the latter pair pressed the point that it seemed utterly mysterious how consciousness could cause such a collapse of the wave-function. In particular, they asked, in virtue of what is consciousness able to affect nature ‘in this peculiar way’?

Their scepticism won the day and the idea that human consciousness could play any role in our understanding of quantum physics was subsequently dismissed by the philosophical community, surviving only in fringe ‘New Age’ discussions. Significantly, however, both sides in the debate invoked London and Bauer’s ‘little book’, as Wigner called it, and both sides also completely misunderstood it!

Bauer was a good physicist, ‘sous-directeur’ of the physics laboratory at the Collège de France in Paris and the first in France to lecture on the new quantum theory, but London was in a different league altogether. After studying with the great physicist Arnold Sommerfeld and working with quantum pioneer Erwin Schrödinger, he became internationally well-known for a number of significant achievements. Nominated for the Nobel Prize five times, he died from a heart condition at the age of 54 and a memorial prize was set up in his honour.

What is notable here, however, is that London also studied phenomenology at university and was considered adept enough for his thesis to be published in the phenomenological ‘yearbook’, where it was noted by Husserl himself. Furthermore, this was no mere youthful intellectual ‘fling’ – London maintained his commitment to phenomenology throughout the 1930s, holding discussions with the philosopher Aron Gurwitsch (who also had a background in physics) while in Paris, for example. This profound phenomenological stance I believe underpins the account that London and Bauer give in their ‘little book’ and undercuts the criticisms of Putnam and Shimony by rejecting the very separation between consciousness and the world that they are based on.

More importantly, the devil, as they say, is in the details of London and Bauer’s manuscript. They begin with what is really quite a startling statement made by two physicists in what has typically been taken to be a textbook presentation of measurement in the quantum context:

‘Without intending to set up a theory of knowledge … physicists were so to speak trapped in spite of themselves into discovering that the formalism of quantum mechanics already implies a well-defined theory of the relationship between the object and the observer, a relation quite different from that implicit in naïve realism, which had seemed, until then, one of the indispensable foundation stones of every science.’

In other words, the subjectivity that Husserl thought had been obscured by the mathematization of science has in fact been recovered in, and set at the very heart of,  that most mathematical of modern theories, quantum mechanics.

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What we have here is not consciousness somehow intervening and mysteriously causing the wave-function to collapse; instead consciousness itself enters into the superposition, until through this inner ‘regard’, a separation is effected between subject and object.

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The relationship that London and Bauer refer to becomes apparent when they come to the crucial analysis of that transition from the quantum superposition to a definite outcome of the measurement. At this point they insist that ‘... it is not a mysterious interaction’ that produces such an outcome; rather, ‘[i]t is only the consciousness of an “I” who can separate himself’ from the superposition by means of ‘… a characteristic and quite familiar faculty which we can call the “faculty of introspection.”’ (London and Bauer 1983, p. 252). By virtue of this “immanent knowledge” the observer is then able to ‘cut the chain of statistical correlations …’ (p. 252) that has extended from the micro-system through to the macroscopic measurement apparatus and the observer herself. What we have here is not consciousness somehow intervening and mysteriously causing the wave-function to collapse, as Putnam and Shimony and later commentators have supposed; instead consciousness itself enters into the superposition, until through this inner ‘regard’, a separation is effected between subject and object.

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It goes without saying that this yields an understanding of quantum theory that is very different from any among the plethora of interpretations currently being entertained by physicists and philosophers of physics. In particular, as London and Bauer emphasised right at the beginning of their ‘little book’, it departs from the ‘naïve realism’ and the associated notion of ‘objectivity’ that is typically assumed in these discussions, offering instead a thoroughly perspectival account.

As far as Husserl was concerned, as a ‘brilliant technician of the method’ a scientist would herself be unable to undertake the reflection required to restore the ‘loss of meaning for life’ since she does not even appreciate the need for it. Fritz London, however, was not just a ‘brilliant technician’ but someone who adopted the phenomenological stance in his own work. Consequently, he was indeed aware of the need for such a fundamental clarification.  Furthermore, given the nature of that work, which involved applying quantum theory to a range of phenomena, from chemical bonding to superconductivity, with subjectivity revealed as laying at the core of the former, it could be taken to be restored across the sciences. As a result, his ‘little book’ with Bauer resolves Husserl’s ‘crisis’ but more than that, it suggests a novel, phenomenologically motivated approach to one of the most fundamental theories in modern physics.

 

Further Reding

S. French, A Phenomenological Approach to Quantum Mechanics: Cutting the Chain of Correlations, Oxford: Oxford University Press, 2023

E. Husserl The Crisis of European Sciences and Transcendental Phenomenology (trans. D. Carr, Northwestern University Press 1954)

H. Wiltsche and P. Berghofer (eds.), Phenomenological Approaches to Physics, Cham: Springer, 2020

J.A. Wheeler and W.H. Zurek (eds), The Theory of Observation in Quantum Mechanics’, in, Quantum Theory and Measurement, Princeton University Press,).

Zahavi, D. (2017), Husserl’s Legacy: Phenomenology, Metaphysics and Transcendental Philosophy, OUP.

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