The Ego Trick (baggini, Julian) / quote 135 of 254
The physical is what fits physicists' equations
the only way physicists can really understand the universe is in the language of mathematics. The fundamental basis of physics is not atoms, or even subatomic particles, but equations. That is why, for all its mysteriousness, dark matter does have all the reality that is needed for physics: it plugs into the equations. Indeed, it is because the equations make it necessary that the existence of dark matter was postulated before it could be detected. So, odd though it may sound, the best definition of the physical world we now have is ‘that which has a place in the equations of physicists’. And one thing you can say with certainty about souls is that they have no place there.