A conviction akin to religious feeling of the rationality or intelligibility of the world lies behind all scientific work of a high order.

Belief in an external world independent of the perceiving subject is the basis of all natural science.

The only real valuable thing is intuition.

As for the search for truth, I know from my own painful searching, with its many blind alleys, how hard it is to take a reliable step, be it ever so small, towards the understanding of that which is truly significant.

Out of the multitude of our sense experiences we take, mentally and arbitrarily, certain repeatedly occurring complexes of sense impression (partly in conjunction with sense impressions which are interpreted as signs for sense experiences of others), and we attribute to them a meaning the meaning of the bodily object.

I believe my theory of relativity to be true. But it will only be proved for certain in 1981, when I am dead.

The greater the doubt, the greater the awakening