Is the World an Illusion?

King’s College philosopher of physics Alexander Franklin wishes to stress that “everyday reality is not an illusion. There really is a world outside our minds." Perhaps so, but there's a more interesting question, I think, concerning the world of which he speaks. More on that in a moment.

Here's an excerpt from a piece at Mind Matters on Professor Franklin's argument:

Popular science often tells us that we are radically deceived by the commonplace appearance of everyday objects and that colour and solidity are illusions. For instance, the physicist Sir Arthur Eddington distinguished in 1928 between two tables: the familiar table and the scientific table, while the former is solid and coloured, the scientific table “is nearly all empty space”.

Eddington then makes the striking claim that “modern physics has by delicate test and remorseless logic assured me that my second scientific table is the only one which is really there”.

Franklin’s essay in response is a plea for Emergentism (the reality we experience emerges from more basic principles), as opposed to what he calls “Illusionism,” the popular belief that it is all an illusion. Along the way, he offers a useful interpretation of the empty space “table,” in terms of quantum physics (the behavior of elementary particles).

Franklin argues that, according to quantum mechanics, an electron in orbit around an atomic nucleus actually occupies the entire orbit, more like the surface of a hollow ball than like a solitary planet orbiting the sun. Thus, there really is no empty space in the orbit and therefore the table's solidity is not an illusion.

This is a bit misleading, though. The atom is in fact mostly empty space. Even if the electrons can be thought of as existing everywhere in their orbits at once, there's a relatively enormous amount of space between orbits. If, for instance, the nucleus of a hydrogen atom were made the size of a bb and placed on second base in a major league stadium, it's lone electron would be orbiting out around the upper deck.

If our hydrogen atom, represented by the bb on second base, was bonded to another hydrogen atom, the nucleus of the second atom, or bb, would be out in the parking lot somewhere. That's a lot of empty space.

Nevertheless, the more interesting question, at least for me, is not whether the solidity of Eddington's table is an illusion but rather how much of what we experience when we observe the table is objectively there in the table and how much of what we observe is actually a creation of our minds.

For example, suppose the table is painted green. We'd say that the table is green, but, of course, the table itself is not any color at all. The sensation of green is in our brains or minds. The paint merely reflects light energy of a certain wavelength to our eye and our visual sense in concert with our brain/mind translates that energy into a sensation of green.

The same is true of the sensations we have of sound, taste, warmth, smell, etc. The stimuli which give rise to these sensations may be generated by objects, but the sensations they produce are in us.

In other words, were there were no perceivers, no one to observe the world, there would be no color, flavor, sound, warmth or odor - just colorless, tasteless, odorless, soundless matter and energy flying about. Just as there'd be no pain if no one felt it, there'd be no color or sound if no one saw or heard it.

This being so, we might ask what is the world in itself really like apart from our perception of it? How much of what we call reality do our senses/brains/minds actually create and how much is objectively independent of our perceptions?

We might also wonder how much of our understanding of the world is a function of our size? Suppose the table appears smooth to us. Would it appear smooth to a bacterium? The table appears solid to us, but pace professor Franklin, it certainly doesn't appear solid to a neutrino, tens of thousands of which pass through every square inch of everything on earth (including us) every second.

Here's another question: How much different would the world appear to us if we had six or seven senses? A man born blind has no concept of light or color. How much different would this world appear to him were he suddenly able to see? Likewise, what experiences would the world present to us if we had the additional senses with which to experience them?

We go through life thinking that the world is just the way we perceive it to be, but why should we think such a thing? The world may be far stranger, far different, than our five senses can discern.