I'm becoming more and more skeptical daily. Everyday is a challenge on what I thought was true.

Ultimately, all things are known because you want to believe you know.

The duty of the man who investigates the writings of scientists, if learning the truth is his goal, is to make himself an enemy of all that he reads.

• Alhazen

If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.

• René Descartes

When you can measure what you are speaking about, and express it in numbers, you know something about it.

• Lord Kelvin

It is natural to man to indulge in the illusions of hope. We are apt to shut our eyes against a painful truth, and listen to the song of the siren till she transforms us into beasts.

• Patrick Henry "Give me liberty or give me death!"