[I think I'm going to focus on metaphysics this month. Not exclusively, but I feel my blog on Solipsism vs. Occum's Razor some months back left some business unfinished.]
There are several questions and problems in Philosophy that are considered particularly difficult or troubling. What is Art, the Sorites Paradox, The Problem of Substance, and The Problem of Consciousness are among them. Although science is closing in on The Problem of Consciousness, there’s a big “maybe” hanging over its head because the biggest question of all is the mother of all the other problems. It is a question every philosopher should be concerned with if any other question or problem is to be resolved – what is reality?
I recently stumbled across an old article (which you can read below) in which the author makes note of how indeterminacy in the quantum world affects what takes place at the macro level of events. More precisely, due to the way in which the quantum world behaves, the very act of observing the (supposed) world of extended objects shapes what appears to be reality for a subject, and this casts doubt on a reality in which things and events are the same for all observers. While Einstein also noted that observations are not in fact the same for all subjects, this was due to a subject’s location in time and space, dimensions through which information must travel and thus, an event may be observed differently in one location and time than another (to say nothing of the inferences one makes of such observations). While many philosophical conundrums have ended in science, this time scientific findings have raised more questions than answers. What happens when something like a particle of light or an electron is observed raises doubt about reality to a whole new level.
The dual nature of light, for example, has been known for some time yet no one – philosopher or scientists – seems to trying very hard to understand what such properties of quantum bits (information) means. (I find this very strange for a species that casts themselves upon a pedestal due to their ability to think in terms of ‘meaning’ whereas other animals supposedly cannot.) What does it mean for light to act as a wave when it is not observed and as a particle when it is observed?
Such a question begets another question; does it mean reality only exists when there is an observer present to collapse the quantum possibilities into a single event? How does the act of observing collapse quantum possibilities into a single event? Physicist Sir Roger Penrose believes gravity is responsible. That’s a tantalizing answer to the question since his answer would allow reality that is not observer-dependent to exist; there just needs to be objects large enough present to exert the effects of gravity over quantum possibilities. But that still leaves us with the question of whether reality exists at the quantum level of events where the very phrase “quantum level of events” becomes a misnomer. And, if we were to think back to the moments following the Big Bang (assuming that is in fact how our universe began), how did a quantum indeterminate world give rise to the force [gravity] necessary to collapse its possibilities into real objects and their events? When I first read it, I wanted to like Penrose’s answer but it, too, raises too many questions.
I was once a hard determinist who believed that the indeterminacies of the quantum world appeared to be indeterminate because of variables we were unable to measure. But if the experiments in the article really do confirm how bizarrely quantum mechanics works, there is no uniform reality, a reality that uniform for all observers. That makes for a possibly disturbing consequence: That one person’s interpretation or observation of reality is as much ‘real’ as the next person’s reality. Such a consequence leads us to another question; if I, as a sole observer, am the only observer that I can even begin to suspect actually exists, is reality mine alone? And, how could reality have created itself until an observer existed; that is, what came first, the possibility of reality or the observer? Did each come into existence simultaneously? Granted, these questions are speculative but I do not regard them to be completely so since as a philosopher am trying to understand what – if anything – scientific findings mean. My speculative questions are, to me, the natural result of what science has unveiled.
Though once a hard determinist, I’m not sure what my current metaphysical view could be categorized as. While I understand how reality is observer dependent, if I believe that and believe that other agents, other observers besides myself exist, there is no single unified reality. This would certainly shore up some of my previous assertions, such as how easily Plato’s Law of Non-Contradiction is broken or that God can both exist and not exist at the same time. But I can’t want to believe those assertions just because I want to. Such assertions should make sense, shouldn’t they? Only, if reality is mine to observe and construe, of course it’s going to make sense.
Quantum Physics Says Goodbye to Reality
Apr 20, 2007 by Jon Cartwright (for Physics Web)
Some physicists are uncomfortable with the idea that all individual quantum events are innately random. This is why many have proposed more complete theories, which suggest that events are at least partially governed by extra "hidden variables". Now physicists from Austria claim to have performed an experiment that rules out a broad class of hidden-variables theories that focus on realism -- giving the uneasy consequence that reality does not exist when we are not observing it (Nature 446 871).
Some 40 years ago the physicist John Bell predicted that many hidden-variables theories would be ruled out if a certain experimental inequality were violated – known as "Bell's inequality". In his thought experiment, a source fires entangled pairs of linearly-polarized photons in opposite directions towards two polarizers, which can be changed in orientation. Quantum mechanics says that there should be a high correlation between results at the polarizers because the photons instantaneously "decide" together which polarization to assume at the moment of measurement, even though they are separated in space. Hidden variables, however, says that such instantaneous decisions are not necessary, because the same strong correlation could be achieved if the photons were somehow informed of the orientation of the polarizers beforehand.
Bell's trick, therefore, was to decide how to orient the polarizers only after the photons have left the source. If hidden variables did exist, they would be unable to know the orientation, and so the results would only be correlated half of the time. On the other hand, if quantum mechanics was right, the results would be much more correlated – in other words, Bell's inequality would be violated.
Many realizations of the thought experiment have indeed verified the violation of Bell's inequality. These have ruled out all hidden-variables theories based on joint assumptions of realism, meaning that reality exists when we are not observing it; and locality, meaning that separated events cannot influence one another instantaneously. But a violation of Bell's inequality does not tell specifically which assumption – realism, locality or both – is discordant with quantum mechanics.
Markus Aspelmeyer, Anton Zeilinger and colleagues from the University of Vienna, however, have now shown that realism is more of a problem than locality in the quantum world. They devised an experiment that violates a different inequality proposed by physicist Anthony Leggett in 2003 that relies only on realism, and relaxes the reliance on locality. To do this, rather than taking measurements along just one plane of polarization, the Austrian team took measurements in additional, perpendicular planes to check for elliptical polarization.
They found that, just as in the realizations of Bell's thought experiment, Leggett's inequality is violated – thus stressing the quantum-mechanical assertion that reality does not exist when we're not observing it. "Our study shows that 'just' giving up the concept of locality would not be enough to obtain a more complete description of quantum mechanics," Aspelmeyer told Physics Web. "You would also have to give up certain intuitive features of realism."
However, Alain Aspect, a physicist who performed the first Bell-type experiment in the 1980s, thinks the team's philosophical conclusions are subjective. "There are other types of non-local models that are not addressed by either Leggett's inequalities or the experiment," he said. "But I rather share the view that such debates, and accompanying experiments such as those by [the Austrian team], allow us to look deeper into the mysteries of quantum mechanics.