When we open our eyes and look at some thing, we see that damn thing. What could be more obvious than that, right? Let’s say you are looking at your dog. What you see is really your dog, because, if you want, you can reach out and touch it. It barks, and you can hear the woof. If it stinks a bit, you can smell it. All these extra perceptual clues corroborate your belief that what you are seeing is your dog. Directly. No questions asked.
Of course, my job on this blog is to ask questions, and cast doubts. First of all, seeing and touching seem to be a bit different from hearing and smelling. You don’t strictly hear your dog bark, you hear its sound. Similarly, you don’t smell it directly, you smell the odor, the chemical trail the dog has left in the air. Hearing and smelling are three place perceptions — the dog generates sound/odor, the sound/odor travels to you, you perceive the sound/odor.
But seeing (or touching) is a two place thing — the dog there, and you here perceiving it directly. Why is that? Why do we feel that when we see or touch something, we sense it directly? This belief in the perceptual veracity of what we see is called naive realism. We of course know that seeing involves light (so does touching, but in a much more complicated way), what we are seeing is the light reflected off an object and so on. It is, in fact, no different from hearing something. But this knowledge of the mechanism of seeing doesn’t alter our natural, commonsense view that what we see is what is out there. Seeing is believing.
Extrapolated from the naive version is the scientific realism, which asserts that our scientific concepts are also real, eventhough we may not directly perceive them. So atoms are real. Electrons are real. Quarks are real. Most of our better scientists out there have been skeptical about this extraploation to our notion of what is real. Einstein, probably the best of them, suspected that even space and time might not be real. Feynman and Gell-Mann, after developing theories on electrons and quarks, expressed their view that electrons and quarks might be mathematical constructs rather than real entities.
What I am inviting you to do here is to go beyond the skepticism of Feynman and Gell-Mann, and delve into Einstein’s words — space and time are modes by which we think, not conditions in which we live. The sense of space is so real to us that we think of everything else as interactions taking place in the arena of space (and time). But space itself is the experience corresponding to the electrical signals generated by the light hitting your retina. It is a perceptual construct, much like the tonality of the sound you hear when air pressure waves hit your ear drums. Our adoption of naive realism results in our complete trust in the three dimensional space view. And since the world is created (in our brain as perceptual constructs) based on light, its speed becomes an all important constant in our world. And since speed mixes space and time, a better description is found in a four dimensional Minkowski geometry. But all these descriptions are based on perceptual experiences and therefore unreal in some sense.
I know the description above is highly circular — I talked about space being a mental construct created by light traveling through, get this, space. And when I speak of its speed, naturally, I’m talking about distance in space divided by time, and positing as the basis for the space-time mixing. This circularity makes my description less than clear and convincing. But the difficulty goes deeper than that. You see, all we have is this cognitive construct of space and time. We can describe objects and events only in terms of these constructs even when we know that they are only cognitive representations of sensory signals. Our language doesn’t go beyond that. Well, it does, but then we will be talking the language, for instance, of Advaita, calling the constructs Maya and the causes behind them Brahman, which stays unknowable. Or, we will be using some other parallel descriptions. These descriptions may be profound, wise and accurate. But ultimately, they are also useless.
But if philosophy is your thing, the discussions of cognitive constructs and unknown causations are not at all useless. Philosophy of physics happens to be my thing, and so I ask myself — what if I assume the unknown physical causes exist in a world similar to our perceptual construct? I could then propagate the causes through the process of perception and figure out what the construct should look like. I know, it sounds a bit complex, but it is something that we do all the time. We know, for instance, that the stars that we see in the night sky are not really there — we are seeing them the way they were a few (or a few million or billion) years ago because the light from them takes a long time to reach us. Physicists also know that the perceived motion of celestial objects also need to be corrected for these light-travel-time effects.
In fact, Einstein used the light travel time effects as the basis for deriving his special theory of relativity. He then stipulated that space and time behave the way we perceive them, derived using the said light-travel-time effects. This, of course, is based on his deep understanding that space and time are “the modes by which we think,” but also based on the assumption that the the causes behind the modes also are similar to the modes themselves. This depth of thinking is lost on the lesser scientists that came after him. The distinction between the modes of thinking and their causation is also lost, so that space and time have become entities that obey strange rules. Like bent spoons.
Photo by General Press1