The only justification for our concepts and systems of concepts is that they serve to represent the complex of our experiences; beyond this they have not legitimacy.
Einstein was once asked how many feet are in a mile. Einstein's reply was "I don't know, why should I fill my brain with facts I can find in two minutes in any standard reference book?
What is the meaning of human life, or, for that matter, of the life of any creature? To know the answer to this question means to be religious. You ask: Does it make any sense, then, to pose this question? I answer: The man who regards his fellow creatures as meaningless is not merely unhappy but hardly fit for life.
It must be conceded that a theory has an important advantage if its basic concepts and fundamental hypotheses are 'close to experience,' and greater confidence in such a theory is certainly justified. There is less danger of going completely astray, particularly since it takes so much less time and effort to disprove such theories by experience. Yet more and more, as the depth of our knowledge increases, we must give up this advantage in our quest for logical simplicity in the foundations of physical theory.
A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended its area of applicability.
A priori one should expect a chaotic world which cannot be grasped by the mind in any way... The kind of order created by Newton's theory of gravitation...is wholly different. Even if the axioms of the theory are proposed by man, the success of such a project presupposes a high degree of ordering of the objective world.... That is the "miracle" which is being constantly reinforced as our knowledge expands.