Blaise Pascal Pensees (#110)

We know the truth not only through our reason but also through our heart. It is through the latter that we know first principles, and reason, which has nothing to do with it, tries in vain to refute them. The skeptics have no other object than that, and they work at it to no purpose. We know that we are not dreaming, but, however unable we may be to prove it rationally, our inability proves nothing but the weakness of our reason, and not the uncertainty of all our knowledge, as they maintain. For knowledge of first principles, like space, time, motion, number, is as solid as any derived through reason, and it is on such knowledge, coming from the heart and instinct, that reason has to depend and base all its argument. The heart feels that there are three spatial dimensions and that there is an infinite series of numbers, and reason goes on to demonstrate that there are no two square numbers of which one is double the other. Principles are felt, propositions proved, and both with certainty though by different means. It is just as pointless and absurd for reason to demand proof of first principles from the heart before agreeing to accept them as it would be absurd for the heart to demand an intuition of all the propositions demonstrated by reason before agreeing to accept them. Our inability must therefore serve only to humble reason, which would like to be the judge of everything, but not to confute our certainty. As if reason were the only way we could learn! Would to God, on the contrary, that we never needed it and knew everything by instinct and feeling! But nature has refused us this blessing, and has instead given us only very little knowledge of this kind; all other knowledge can be acquired only by reasoning. That is why those to whom God has given religious faith by moving their hearts are very fortunate, and feel quite legitimately convinced, but to those who do not have it we can only give such faith through reasoning, until God gives it by moving their heart, without which faith is only human and useless for salvation.

I can certainly imagine a man without hands, feet, or head, for it is only experience that teaches us that the head is more necessary than the feet. But I cannot imagine a man without thought; he would be a stone or an animal.