@centrox,
Quote:I was thinking about a universe in which mathematics was different from in ours, mathematics being historically and culturally contingent human activity, of course. Suppose there is a universe where two plus two equals three; where does the (to us) missing one go? If two couples meet up, does one of the people vanish? (Schrödinger's wife?) Etc.
This isn't that difficult.
My kids play Minecraft. This is a pretty clever computer simulated world with some very odd laws of Physics. Once you understand the laws of Physics in this simulated world... it makes perfect sense. Of course many people (well... players) in the world have figured out how to use the laws of physics in the game world to their advantage... much as you and I have figured out to used the laws of physics in our world to ours.
In Minecraft, gravity works completely differently. If something is falling, it will continue to fall until it hits something... however if something is not falling, then it will continue to stay stationary even if there is nothing holding it up. So you can put a one block on top of another (a stable structure). If you move the bottom block, the top block will stay stationary (where in our world you would expect it to drop). So you can make structures that are "hovering" in the air.
In Minecraft there is no conservation of mass. There are "blocks" (all objects in this universe are blocks) that generate "matter". The most interesting of these is water. A water source block will continue to generate water forever with no input.
If an Artificial Intelligence ever exists in the Minecraft Universe, it will learn to live with and function in these laws of Physics that are different than ours. The in-game laws of gravity and matter would seem quite obvious and natural to the in-game intelligence. The question is
whether this in game intelligence would have any way to conceive of our laws on gravity on its own.
We develop an intuition based on our experience of the laws of Physics in the universe we inhabit. They seem perfectly logical... but they only seem that way because it is all we know.