Topics Science

Question I would like to know the panel's view on: 1. Did the laws of physics theoretically exist before the Big Bang, just waiting to come into force? Are these laws the only way they could possibly be? 2. Is there any reason why science should eventually hit a brick wall beyond which stuff is unknowable (rather than unknown)? Many thanks for all your comments on this wonderful site.

Accepted:
December 16, 2006

Comments

Thank you for your interesting questions.

The standard view is that space and time (or, more accurately, spacetime -- since space and time are not independent entities according to the theory of relativity) came into existence with the Big Bang. So there was no time before the Big Bang. So the laws of physics were not existing before the Big Bang, just waiting to come into force.

However, there is a sense in which many laws of physics are waiting to come into force. Suppose it is a law of physics that two electrical point charges of 1.234 statcoulombs and 5.678 statcoulombs, at a distance of 1 centimeter, exert upon each other a mutually repulsive force of 10.234 dynes. There was presumably a first moment in the history of the universe when there were two point charges of those quantities, 1 centimeter apart. (Or perhaps there has never yet been such a moment. Perhaps there never ever will be two such point charges in the entire history of the universe.) The law governing two such point charges presumably existed even before that first moment. Newton's first law of motion, which concerns bodies the feel no forces at all, has never covered any actual cases, since every body feels the gravitational influences of others.

As to whether the laws of nature are the only way they could possibly be: this is a controversial question. The standard view is that the laws of nature could have been otherwise; there would be no logical contradiction in a universe where, for instance, gravity is an inverse-cubed force (or gravity did not exist and an inverse-cubed force exists in its place). However, it has been speculated that the laws of nature could not have been a *little* bit different; one *small* change would ramify to other changes, via other laws, resulting in divisions by zero or probabilities greater than 1 or less than 0, or other undefined quantities. Even on this view, though, the laws could have been *very* different.