Let nothing go that you could keep; for, if it went, you couldn’t get it back.
It is impossible to found a civilization on fear and hatred and cruelty.
It would never endure.
The laws are:
1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
3. Any sufficiently advanced technology is indistinguishable from magic.
A real fisherman is not someone who has caught a lot, but someone who has proved that it was impossible.
There cannot be two swords in one sheath.