It is unwise to be too sure of one's own wisdom. It is healthy to be reminded that the strongest might weaken and the wisest might err - Mahatma Gandhi
It is not clear that intelligence has any long-term survival value - Stephen Hawking
Ye cannae change the laws of physics. [Engineer Scott]
The Three Laws of Arthur C Clarke, 1917 to 2008
Law 1. When a distinguished but elderly scientist says something is possible, he is almost certainly right. When he says it is impossible, he is very probably wrong.
Law 2. But the only way of discovering the limits of the possible is to venture a little way past them into the impossible.
Law 3. Any sufficiently advanced technology is indistinguishable from magic.
I like the next two:
There's no sense in being precise when you don't even know what you're talking about. [John von Neumann, 1903 to 1957]
In theory, there is no difference between theory and practice, but in practice, there is. Unknown