From many people

[puddingcat]

And the tag line: Physics is to maths what sex is to masturbation.

Comments

[marcushill.livejournal.com]

Nah, masturbation is applied maths. Pure maths is subscribing to porn and not looking at it - after all, you've demonstrated that sex exists, and that's sufficient.

[puddingcat.livejournal.com]

Surely porn is still *demonstrating* the existence of sex. Proving it exists just takes your own existence.