In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.
When you're old and your eyes are dim, There ain't no old shep gonna happen again
We'll still go walking down country lanes, I'll sing the same old song
Hear me call your name