The "second sight" possessed by the Highlanders in Scotland is actually a foreknowledge of future events. I believe they possess this gift because they don't wear trousers.

It is almost everywhere the case that soon after it is begotten the greater part of human wisdom is laid to rest in repositories.

Everyone is perfectly willing to learn from unpleasant experience - if only the damage of the first lesson could be repaired.

Doubt everything at least once, even the sentence "Two times two is four."

A man of spirit must not think of the word difficulty as so much as existing. Away with it!

The Greeks possessed a knowledge of human nature we seem hardly able to attain to without passing through the strengthening hibernation of a new barbarism.

Be attentive, feel nothing in vain, measure and compare: this is the whole law of philosophy.