Poincare in Science and Method

"What, in fact, is mathematical discovery?  
It does not consist in making new combinations with mathematical entities 
that are already known.  That can be done by anyone, and 
the combinations that could be so formed would be infinite in number, and 
the greater part of them would be absolutely devoid of interest.  
Discovery consists precisely in not constructing useless combinations, but 
in constructing those which are useful, which are an infinitely small minority.  
Discovery in discernment, selection.

"Mathematical facts worthy of being studied are those which, 
by their analogy with other facts, 
are capable of leading us to the knowledge of a mathematical law, 
in the same way that experimental facts lead us to the knowledge of a physical law.  
They are those which reveal unsuspected relations between other facts, 
long since known, but wrongly believed to be unrelated to each other."