We cannot believe that the interconnections of the parts of the universe are logical, because we hold that scientific laws are to be discovered by observation, not by reasoning alone.
 Bertrand Russell, A History of Western Philosophy (1945). copy citation

Context

“It was of the essence of his system, ethically as well as metaphysically, to maintain that everything could be demonstrated, and it was therefore essential to produce demonstrations. We cannot accept his method, but that is because we cannot accept his metaphysic. We cannot believe that the interconnections of the parts of the universe are logical, because we hold that scientific laws are to be discovered by observation, not by reasoning alone. But for Spinoza the geometrical method was necessary, and was bound up with the most essential parts of his doctrine.
I come now to Spinoza’s theory of the emotions. This comes after a metaphysical discussion of the nature and origin of the mind, which leads up to the astonishing proposition that “ the human mind has an adequate knowledge of the eternal and infinite essence of God. ”” source