On the other hand... we have to give up the notion of an absolute localization of the particles in a theoretical model. This seems to me to be the correct theoretical interpretation of Heisenberg's indeterminacy relation. And yet a theory may perfectly well exist, which is in a genuine sense an atomistic one (and not merely on the basis of a particular interpretation), in which there is no localizing of the particles in a mathematical model.
If you wish to learn from the theoretical physicist anything about the methods which he uses... Don't listen to his words, examine his achievements. For to the discoverer in that field, the constructions of his imagination appear so necessary and so natural that he is apt to treat them not as the creations of his thoughts but as given realities.
Conclusions obtained by purely rational processes are, so far as Reality is concerned, entirely empty. It was because he recognized this, and especially because he impressed it upon the scientific world that Galileo became the father of modern physics and in fact of the whole of modern natural science.
A complete system of theoretical physics consists of concepts and basic laws to interrelate those concepts and of consequences to be derived by logical deduction.
[I]f we conceive Euclidean geometry as the science of the possibilities of the relative placing of actual rigid bodies and accordingly interpret it as a physical science, and do not abstract from its original empirical content, the logical parallelism of geometry and theoretical physics is complete.
It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible...
Have we any right to hope that experience will guide us aright, when there are theories (like classical mechanics) which agree with experience to a very great extent, even without comprehending the subject in its depths? ...there is the correct path and, moreover... it is in our power to find it. ...in Nature is actualized the ideal of mathematical simplicity. ...pure mathematical construction enables us to discover the concepts and the laws...
[E]xperience... remains the sole criterion of the serviceability of a mathematical construction for physics, but the truly creative principle resides in mathematics. ...pure thought is competent to comprehend the real, as the ancients dreamed.