The language of physics is mathematics, and it cannot be done honestly without mathematics. That makes it inaccessible. The language of literature is English or Chinese or whatever, and that makes it accessible. And literature is about the human condition. Physics is about the nonhuman condition. It’s not a taste that all human beings have.
People are also social creatures, and literature fits in with that. Physics is perceived as a lonesome, nerdy kind of enterprise that has very little to do with human feelings and the things that excite people day-to-day about each other. Yet physicists in their own working environment are very social creatures.
There is a philosophy that says that if something is unobservable – unobservable in principle – it is not part of science. If there is no way to falsify or confirm a hypothesis, it belongs to the realm of metaphysical speculation, together with astrology and spiritualism. By that standard, most of the universe has no scientific reality – it’s just a figment of our imaginations.
The universe is vastly bigger than the portion that we can see; and, on a very large scale it is as varied as possible. In other words, rather than being a homogeneous, mono-colored blanket, it is a crazy-quilt patchwork of different environments. This is not an idle speculation. There is a growing body of empirical evidence confirming the inflationary theory of cosmology, which underlies the hugeness and hypothetical diversity of the universe.
Meanwhile string theorists, much to the regret of many of them, are discovering that the number of possible environments described by their equations is far beyond millions or billions. This enormous space of possibilities, whose multiplicity may exceed ten to the 500 power, is called the Landscape. If these things prove to be true, then some features of the laws of physics (maybe most) will be local environmental facts rather than written-in-stone laws: laws that could not be otherwise. The explanation of some numerical coincidences will necessarily be that most of the multiverse is uninhabitable, but in some very tiny fraction conditions are fine-tuned enough for intelligent life to form.
You are a victim of your own neural architecture which doesn’t permit you to imagine anything outside of three dimensions. Even two dimensions. People know they can’t visualise four or five dimensions, but they think they can close their eyes and see two dimensions. But they can’t. When you close your eyes and try to see two dimensions you’ll always see a surface embedded in three dimensions.
Is there something special about three dimensions? No. There is something special about your neural architecture. You evolved in a world where everything inside your brain is hooked up and geared to be able to see three dimensions and nothing else.
I don’t believe I’ve ever in my life heard a physicist actually refer to ‘covariant indices’ and 'contravariant indices’. They just call them 'upstairs’ and 'downstairs’, 'cause nobody can ever remember which is which.
The search for a unified theory of physics has led theorists far and wide for answers. String theory is a major contender in the race to find the unified theory, but there are things that it doesn’t explain. Surprisingly, the answers have been coming from cosmologists. Stanford University physicist Leonard Susskind explains how a vast energy landscape becomes populated with bubbles, each with their own complex landscapes.