My parents are private investigators for God's sake.

This hypothesis (Parallel hypothesis) would not destroy itself at all easily.

The first object of my endeavours was the means to become perfect and happy.

I should almost therefore put forward the proposal that the third hypothsis (angle sum of a triangle less than two right angles) holds on the surface of an imaginary sphere.

I bought some books in order to learn the first principles of philosophy.

Yeah, my dad bought me a guitar when I was like 10, and I didn't really want it then.

Proofs of the Euclidean [parallel] postulate can be developed to such an extent that apparently a mere trifle remains. But a careful analysis shows that in this seeming trifle lies the crux of the matter; usually it contains either the proposition that is being proved or a postulate equivalent to it.