What did Stephen Hawking mean with “not demanded by logic or physical principle”?

In his book, "The Grand Design", physicist Stephen Hawking said:

"It appears that the fundamental numbers, and even the form, of the apparent laws of nature are not demanded by logic or physical principle. The parameters are free to take on many values and the laws to take on any form that leads to a self-consistent mathematical theory, and they do take on different values and different forms in different universes."

My question is: What does it mean that laws of nature are not demanded by logic or physical principle?