Chris Knight, the finest fictional physicist of our time, once said "All science. No Philosophy. Wrong." It's true that an understanding of existence outside of equations is vital for scientists, both in terms of enjoying life and avoiding things like Agent Orange, but beware careless combination of the two. A science/philosophy mixture can lead to metaphysical claims that the laws of physics are nothing but local zoning ordinances, as demonstrated by Lee Smolin.
Smolin is author of "the fecund universes theory" of cosmology which suggests that the rules of biology apply on the grandest scales, and is often referred to as "cosmological natural selection". Smolin summarized the idea in his book, The Life of the Cosmos.
The theory surmises that a collapsing black hole causes the emergence of a new universe on the "other side", whose fundamental constant parameters (speed of light, Planck length and so forth) may differ slightly from those of the universe where the black hole collapsed. Each universe therefore gives rise to as many new universes as it has black holes.
The Perimeter Institute theoretical physicist got together with philosopher Roberto Unger and arrived at three radically new conclusions. The first is that there is only one universe - the idea of a multiverse might be awesome science fiction, and essential to the slightly less credible string theory, but there's no reason to base your worldview on worlds where the Nazis won or the universal constant of gravitation has a different value.
The second idea is that time is real. Remember when you read that first sentence? Okay, you agree with us - this is one of those discussions that takes place at a level regular humans don't argue at. Some say that all of existence is a crystal of reality that we happen to move through, Dr Manhattan style, which is wonderfully imaginative but displays incredible cognitive disconnection. Even speaking the words aloud demonstrates the passage of time, and most arguments beyond that depend on bringing the debate to an extremely specific linguistic field of hyper-definitions that the opponent hasn't wasted their life learning, and will therefore "lose" at. Luckily for us, Lee agrees that time actually exists and we can move on to the real problem: the idea of physics as local rules.
His argument that physics can change over time and space is apparently based on an extremely specific strawman argument which depends on separating experimental procedure into initial conditions and laws. He says you can only arrive at laws by examining a large "configuration space" of possible setups. In the lab you can set up a large number of tests, in cosmology you can look at a wide variety of situations, so in both you can arrive at laws. His argument is that since you can't actually rearrange the stars themselves to set up different initial conditions in each place, you can't make conclusions about the physical laws there. He uses many, many more words to describe this idea.
It's all very intellectually stimulating, but mainly demonstrates the difference between metaphysics and useful physics. If you're going to claim that general relativity stops working beyond some sort of interstate-of-existence line, the burden of proof is on you to show that's the case - and strawman arguments on the nature of experimentation aren't going to cut it. You can say that the plank constant is a variable over time and space, but when we want to build an bridge or a fusion reactor we're going to stick with our silly, provincial, non-new-book-publishing "actual physics." And that's the difference.
Posted by Luke McKinney