“I refute it thus!” Samuel Johnson famously dismissed Bishop George Berkeley's argument for the unreality of matter by kicking a large stone (Boswell, 1823). In the light of modern physics, however, Johnson's simple reasoning evaporates. Apparently solid matter is revealed, on closer inspection, to be almost all empty space, and the particles of which matter is composed are themselves ghostly patterns of quantum energy, mere excitations of invisible quantum fields, or possibly vibrating loops of string living in a ten-dimensional space–time (Greene, 1999). The history of physics is one of successive abstractions from daily experience and common sense, into a counterintuitive realm of mathematical forms and relationships, with a link to the stark sense data of human observation that is long and often tortuous. Yet at the end of the day, science is empirical, and our finest theories must be grounded, somehow, “in reality.” But where is reality? Is it in acts of observation of the world made by human and possibly non-human observers? In records stored in computer or laboratory notebooks? In some objective world “out there”? Or in a more abstract location? THE GROUND OF REALITY When a physicist performs an experiment, he or she interrogates nature and receives a response that, ultimately, is in the form of discrete bits of information (think of “yes” or “no” binary answers to specific questions), the discreteness implied by the underlying quantum nature of the universe (Zeilinger, 2004).
“I refute it thus!” Samuel Johnson famously dismissed Bishop George Berkeley's argument for the unreality of matter by kicking a large stone (Boswell, 1823). In the light of modern physics, however, Johnson's simple reasoning evaporates. Apparently solid matter is revealed, on closer inspection, to be almost all empty space, and the particles of which matter is composed are themselves ghostly patterns of quantum energy, mere excitations of invisible quantum fields, or possibly vibrating loops of string living in a ten-dimensional space–time (Greene, 1999). The history of physics is one of successive abstractions from daily experience and common sense, into a counterintuitive realm of mathematical forms and relationships, with a link to the stark sense data of human observation that is long and often tortuous. Yet at the end of the day, science is empirical, and our finest theories must be grounded, somehow, “in reality.” But where is reality? Is it in acts of observation of the world made by human and possibly non-human observers? In records stored in computer or laboratory notebooks? In some objective world “out there”? Or in a more abstract location? THE GROUND OF REALITY When a physicist performs an experiment, he or she interrogates nature and receives a response that, ultimately, is in the form of discrete bits of information (think of “yes” or “no” binary answers to specific questions), the discreteness implied by the underlying quantum nature of the universe (Zeilinger, 2004).
“I refute it thus!” Samuel Johnson famously dismissed Bishop George Berkeley's argument for the unreality of matter by kicking a large stone (Boswell, 1823). In the light of modern physics, however, Johnson's simple reasoning evaporates. Apparently solid matter is revealed, on closer inspection, to be almost all empty space, and the particles of which matter is composed are themselves ghostly patterns of quantum energy, mere excitations of invisible quantum fields, or possibly vibrating loops of string living in a ten-dimensional space–time (Greene, 1999). The history of physics is one of successive abstractions from daily experience and common sense, into a counterintuitive realm of mathematical forms and relationships, with a link to the stark sense data of human observation that is long and often tortuous. Yet at the end of the day, science is empirical, and our finest theories must be grounded, somehow, “in reality.” But where is reality? Is it in acts of observation of the world made by human and possibly non-human observers? In records stored in computer or laboratory notebooks? In some objective world “out there”? Or in a more abstract location? The ground of reality When a physicist performs an experiment, he or she interrogates nature and receives a response that, ultimately, is in the form of discrete bits of information (think of “yes” or “no” binary answers to specific questions), the discreteness implied by the underlying quantum nature of the universe (Zeilinger, 2004). Does reality then lie in the string of bits that come back from the set of all observations and experiments – a dry sequence of ones and zeros? Do these observations merely transfer really-existing bits of information from an external world reality to the minds of observers, or are the bits of information created by the very act of observation/experiment? And – the question to which this entire discussion is directed – are bits of “classical” information the only sort of information that count in the reality game, or does an altogether different form of information underpin reality? In short, where is the ontological ground on which our impression of a really-existing universe rests?
The new physics just described was still based largely on Newtonian ideas. Indeed, in its theoretical aspects, it might not unfairly be described as a final attempt to explain the world in materialistic terms—as particles being pushed and pulled about in space and time. Nevertheless, the new physics had found it necessary to abolish most of the forces of pushing and pulling, replacing the gradual changes of motion of the particles under these forces by sudden and unpredictable jumps. These appeared to involve violations of the law of causality, both in the disintegration of radioactive atoms and also in the internal changes of ordinary atoms. We seemed to see Fate defying this law as she picked out certain atoms for disintegration or collapse and, by her apparently capricious acts, sent the universe along one path or another according to her whim. On such lines the new physics had explained many phenomena which had hitherto seemed inexplicable, but it had by no means met with complete success. For instance, while it gave a perfect interpretation of the simplest spectrum of all, namely that of the hydrogen atom, it failed with more complex spectra. This was not necessarily a fatal objection; a few emendations and possibly a few new ad hoc assumptions might have effected a complete reconciliation, although this seems improbable.
After we came out of the church, we stood talking for some time together of Bishop Berkeley's ingenious sophistry to prove the nonexistence of matter, and that every thing in the universe is merely ideal. I observed that though we are satisfied his doctrine is not true, it is impossible to refute it. I never shall forget the alacrity with which Johnson answered, striking his foot with mighty force against a large stone, till he rebounded from it – “I refute it thus.” – James Boswell, The Life of Samuel Johnson There is nothing … more abstract than reality. – Giorgio Morandi, interview with Edouard Roditi A bad habit is something you do, without being fully aware of it, that makes life harder than it needs to be. It is a bad habit of physicists to take their most successful abstractions to be real properties of our world. Since the distinction between real and abstract is notoriously problematic, you might wonder what it means to wrongly confer reality on something abstract. I shall illustrate our habit of inappropriately reifying our successful abstractions with several examples. Perhaps the least controversial examples are provided by quantum mechanics. The quantum state may well be the most powerful abstraction we have ever found. Are quantum states real? In considering what that question might mean, recall that in the early days Erwin Schrödinger thought that the quantum state of a particle—in the form of its wavefunction—was as real a field as a classical electromagnetic field is real. He abandoned that view when he recognized that nonspreading wavepackets were a peculiarity of the harmonic oscillator, and that the wavefunction of N particles is a field only in a 3 N -dimensional space. But that does not prevent advocates of the de Broglie–Bohm “pilot wave” interpretation of quantum mechanics from taking the wavefunction of N particles to be a real field in 3 N -dimensional configuration space. They give that high-dimensional configuration space just as much physical reality as the rest of us ascribe to ordinary three-dimensional space. The reality of the wavefunction is manifest in its ability to control the motion of (real) particles, just as a classical electromagnetic field is able to control the motion of classical charged particles.
I describe characteristic phenomena of quantum physics that suggest that reality appears to us in two domains: the open and well‐known domain of empirical, material things—the realm of actuality—and a hidden and invisible domain of nonempirical, non‐material forms—the realm of potentiality. The nonempirical forms are part of physical reality because they contain the empirical possibilities of the universe and can manifest themselves in the empirical world. Two classes of nonempirical states are discussed: the superposition states of microphysical entities, which are nonempirical because observation destroys them, and the virtual states of material systems, which are nonempirical because they are empty. The non‐empirical part to physical reality represents a predetermined and hidden order that exists before it is empirical, and the visible world is an emanation out of it. I discuss consequences for our understanding of human nature, the origin of life, and human values. Reality is an indivisible wholeness that is aware of its processes, like a Cosmic Spirit, and it reveals its awareness in the mindlike properties of elementary processes as well as in the human consciousness. Thus, one is led to G. W. F. Hegel's thesis that the Cosmic Spirit is thinking in us.
Abstract As the end of the nineteenth century, the search for Nature’s basic laws seemed close to its goal. There was a sense of a task accomplished. Physics presented an orderly scene that fit the proper Victorian mood of the day. Objects both on Earth and in the heavens behaved in accord with Newton’s laws. So, presumably, did atoms. The nature of atoms was unclear. But to most scientists the rest of the job of describing the universe seemed a filling in of the details of the Great Machine.
Bishop Berkeley, meet Professor Schrödinger! So one might introduce the two main protagonists, so to speak, of Bruce Gordon’s paper. Not, perhaps, likely companions in real life, even if we overlook the chronological discrepancy. But they are similar at least in their disregard for what G. E. Moore termed the “common-sense view of the world.” Samuel Johnson, notoriously, claimed to have refuted Berkeley by kicking a stone. Judged by the strict epistemological standards that issue from Cartesian-style skepticism, his refutation may have failed, but before the bar of common sense, it is Johnson who prevails. And many proponents of quantum mechanics positively revel in the comeuppance their theory delivers to the everyday view of the world that we normally take for granted. What could be more propitious, then, than to press quantum mechanics into service as a support for subjective idealism?