Berkeley’s Ideas in Physics
Not only did Bishop George Berkeley’s ideas influence subsequent philosophical thought, they also influenced thought in the physical sciences. Berkeley’s ideas resurface in the works of physicist Ernst Mach. Albert Einstein cited Mach as one of the influences of his theory of relativity, and Berkley’s ideas of motion appear in Einstein’s work. Although Einstein did not embrace idealism as Berkeley did, subsequent quantum physicists did. Berkeleyian ideas are immersed in quantum theory, and some physicists are making proclamations about the universe surprisingly similar to Berkeley’s 18th century notions. Berkeley’s empiricist philosophy played an important role in the development of physics; even today Berkeley’s ideas apply to the world of quantum mechanics.
Ernst Mach was an Austrian physicist who also wrote in the fields of philosophy and psychology. Mach’s ideas are very Berkeleyian in nature. Berkeley believed that matter was a collection of sensations existing only in the mind. This view leads to many philosophical and physical consequences. Mach writes in his Analysis of Sensations:
Inasmuch as it is possible to take away singly every constituent part without destroying the capacity of the image to stand for the totality and to be recognized again, it is imagined that it is possible to subtract all the parts and to have something still remaining. Thus naturally arises the philosophical notion, at first impressive, but subsequently recognized as monstrous, of a “thing-in-itself,” different from its “appearance,” and unknowable… Thing, body, matter, are nothing apart from the combinations of the elements, - the colours, sounds, and so forth – nothing apart from their so-called attributes (6-7).
Mach is exploring the contradictory nature of a thing-in-itself just as Berkeley did. Berkeley writes, “it is plain that the very notion of what is called Matter or corporeal substance involves a contradiction in it” (Berkeley 307). The refutation of the concept of abstract ideas is central to Berkeley’s argument that matter does not exist outside of perceptions; Mach makes a similar argument in his Analysis of Sensations:
What do we do when we abstract? What is an abstraction? What is a concept? Is there a sensational presentation-image corresponding to the concept? I cannot represent to myself a man in general. I can at most represent to myself a particular man, or perhaps one combining such accidental peculiarities of different men as are not exclusive of each other. A universal triangle, which is at once right-angled and equilateral, cannot be imagined (321).
Berkeley uses the same examples of a general man and a general triangle in his refutation of abstract general ideas. Berkeley writes, “I deny that I can abstract from one another, or conceive separately, those qualities which it is impossible should exist so separated; or that I can frame a general notion, by abstracting from particulars” (Berkeley 299).
Berkeley battles the skeptic with his philosophy by arguing that the sensations we receive from God are the only reality. There is not anything outside of our sensations that we cannot have knowledge of. The only things that exist are our perceptions. And if the only real things are those things which we perceive then all of the knowledge we receive through the senses will be true knowledge. This is demonstrated as Berkeley writes in A Treatise Concerning the Principles of Human Knowledge:
So long as men thought that real things subsisted with out the mind, and that their knowledge was only so far forth real as it was conformable to real things, it follows they could not be certain they had any real knowledge at all. For how can it be known that the things which are perceived are conformable to those which are not perceived, or exist without the mind? (327).
Mach parallels Berkeley as he writes, “There is no rift between the psychical and the physical, no inside and outside, no “sensation” to which an external “thing,” different from sensation, corresponds” (Mach 310). Mach gets rid of skepticism the same way Berkeley does, by arguing that the only way we gain knowledge is through sensations, and that these sensations are very much real.
If we can only get knowledge from sensation then it follows that physics must be done through observation. This is view central to Mach’s thinking, which still exists in physics today. Mach believed “that all knowledge is derived from sensation; thus, phenomena under scientific investigation can be understood only in terms of experiences, or “sensations,” present in the observation of the phenomena. This view leads to the position that no statement in natural science is empirically verifiable” (Institute of physics). Most theories today are not accepted without empirical evidence from results of experiments performed in the world.
From the view that we can only have knowledge through sensation Berkeley forms his view on how one should go about the natural sciences. Berkeley believed that God presents sensations to humans in a very ordered way so that they can predict what will happen in nature and use this to their benefit and live in a sane manner. Berkeley writes, “Now the set rules or established methods wherein the Mind we depend on excites in us the ideas of sense, are called the laws of nature; and these we learn by experience, which teaches us that such and such ideas are attended with such and such other ideas, in the ordinary course of things” (Berkeley 313). By coming to understand this order of the world we can predict what will happen in the universe, and form natural laws. Berkeley thinks finding these natural laws should be the physicist’s objective. In The Principles Berkley writes:
And it is the searching after and endeavoring to understand those signs instituted by the Author of Nature that ought to be the employment of the natural philosopher; and not the pretending to explain things by corporeal causes, which doctrine seems to have too much estranged the minds of men from that active principle, that supreme and wise Spirit “in whom we live, move, and have our being (322).
Mach has a similar scientific method. Mach writes, “For us, therefore, the world does not consist of mysterious entities, which by their interaction with another, equally mysterious entity, the ego, produce sensations, which alone are accessible. For us, colors, sounds, spaces, times … are provisionally the ultimate elements, whose given connexion it is our business to investigate” (Mach 29-30). Mach adopted the Berkeleyian philosophy that we should find natural laws based on the connection between sensations.
Mach gave many arguments refuting Newton’s concept of absolute space similar to Berkeley’s arguments. Berkeley’s ideas of relative motion come up in Mach’s writings. Berkeley believed that all motion is relative, and that there was no absolute motion. Berkeley writes, “I must confess it does not appear to me that there can be any motion other than relative” (Berkeley 333). In The Science of Mechanics Mach writes, “All masses and all velocities, and consequently all forces, are relative” (Mach 279). These relativistic theories, through the medium of Mach, would later influence one of the greatest scientific minds of all time, Albert Einstein.
Albert Einstein radically changed our outlook on the world with his theory of relativity. Berkeley’s notions of motion are similar to those that Einstein developed in his theory. A foundation of relativity is that all motion is relative. Before one asks how fast something is going one must ask the question, relative to what? Berkeley writes, “I must confess it does not appear to me that there can be any motion other than relative” (Berkeley 333). This very notion is expressed by Einstein, “It was at all times clear that, from the point of view of the idea it conveys to us, every motion must be considered only as a relative motion” (Einstein 61). Again, Einstein writes, “it is clearly seen that there is no such thing as an independently existing trajectory, but only a trajectory relative to a particular body of reference” (Einstein 11). Even though the body of reference for Berkeley is always the mind whereas Einstein simply refers to inertial reference frames, one can see the similarity in the positions.
Einstein’s famous equation, E=mc^2, also bears some resemblance to Berkley’s thought. Berkeley believed that matter is not fundamentally real. Einstein showed that matter isn’t as concrete as most people think it is. Einstein’s equation says that mass can be converted to energy by multiplying it by the speed of light squared. So a piece of matter, which most consider to be a corporeal substance, can be converted to energy, the non-corporeal ability to do work. Although Einstein adopted the concept of relativity that was originally in Berkeley’s writings, Einstein did not adopt Berkeley’s idealism. In fact Einstein was vehemently opposed to the idealistic properties that emerge quantum mechanics.
Quantum mechanics is a theory that describes the world at the microscopic level. The ideas that some physicists have about the implications of quantum mechanics are strange and sometimes Berkeleyian in nature. Quantum mechanics challenges traditional thought in the same way that Berkeley’s idealism does. Berkeley writes, “Qualities, as hath been shewn, are nothing else but sensations or ideas, which exist only in a mind perceiving them” (Berkeley 325). Berkeley believes that not only qualities, but all matter, and all things we perceive through the sensations exist only in the mind. The idea of an object only having existence through a perceiving mind is a notion that pervades quantum theory.
“One of the principal founders of quantum theory, the German physicist Werner Heisenberg, discovered mathematical relationships suggesting that at the submicroscopic, or quantum, level, reality cannot be separated from the act of observation; merely measuring some property of an electron or other quantum particle causes a change in the thing being measured” (Browne). Berkeley’s thought is better realized in the theories of another quantum physicist, Erwin Schrödinger. Schrödinger theorized that before an object is observed it does not exist in a definite state, but rather as a superposition of all possible states. Only when observed does a particle collapse into reality, actualizing one of its many possibilities. What this means is that before observation, a particle doesn’t have a definite existence! As physicist N. David Mermin puts it, “We now know that the moon is demonstrably not there when nobody looks” (Mermin 50). This Berkeleyian idea is not a minority view. The majority of quantum theorists hold that, “At the quantum level, the essential properties of subatomic particles do not exist until the conscious mind brings it into existence” (Kolak 397). Esse is percipi is perhaps a fundamental property of our universe.
David Bohm is another physicist who believes strongly in the idea that consciousness plays a major role in the nature of reality. Bohm developed his theory of the implicate order based on the EPR Effect, which demonstrates that “two quantum entities that have interacted with each other retain a power of mutual influence however far apart they may separate from each other” (Polkinghorne 96). This was referred to by Einstein as “spooky action at a distance”. Bohm thought that though it seemed the particles in the EPR effect were communicating instantaneously faster than the speed of light, this really wasn’t the case, but rather the particles’ separateness was an illusion (Pratt). Bohm theorized that there is a wholeness to the universe, a kind of implicate order. Bohm’s views are similar to Berkeley’s argument against space. Someone might object to Berkeley by saying that “we see things actually without or at distance from us, and which consequently do not exist in the mind; it being absurd that those things which are seen at the distance of several miles should be as near to us as our own thoughts” (Berkeley 315). Berkeley held that the distance between the two objects does not really exist, but is only a product of sensations. In his New Theory of Vision Berkeley explained this by declaring that we only see in 2-D, but we learn to see in 3-D through kinesthetic.
Berkeley’s thought resurfaces again in the physics and philosophy of John Wheeler, who holds an idealist position similar to Berkeley’s: not only in the idea that esse is percipi, but also in his concept of God (Kolak 400). Wheeler theorizes that there exists “an ultimate observer who brings forth the entire universe into existence and coordinates into coherence all the observations of the conscious entities within it” (Kolak 400). We can see the similarities between Wheeler’s concept of God and Berkeley’s as Berkeley writes, “A spirit is one simple, undivided, active being—as it perceives ideas it is called the understanding, and as it produces or otherwise operates about them it is called the will” (Berkeley 312). God perceives everything and is the spirit that produces the sensations that are the reality that the human mind perceives.
Traces of Berkeley’s thought can be traced throughout the history of physics to the present day. Berkeley’s major contribution through Mach was the idea that we can only have knowledge empirically through sensations. This view played a major role in the development of physics and is still applied today. Berkeley’s thought resurfaces in what many hold to be one of the greatest scientific achievements ever, Einstein’s Theory of Relativity. But what is perhaps most astounding is the fact that in quantum theory today physicists are coming to conclusions remarkably similar to those that Berkeley held in the 18th century. Berkeley’s ideas are testimonial to the power of thought and philosophy. Berkeley’s ideas cannot be disregarded as philosophical absurdities. Berkeley’s arguments still have power today and are relevant in our never-ending quest to understand the nature of the universe.
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