The key of their prison cells

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Santayana’s neat and pointed explanation as to why knowledge cultures need breadth. Science as usually understood is incomplete in this respect, as are all specialisms.

A consequence of this incoherence in experience is that science is not absolutely single but springs up in various places at once, as a certain consistency or method becomes visible in this or that direction.

These independent sciences might, conceivably, never meet at all; each might work out an entirely different aspect of things and cross the other, as it were, at a different level.

This actually happens, for instance, in mathematics as compared with history or psychology, and in morals as compared with physics. Nevertheless, the fact that these various sciences are all human, and that here, for instance, we are able to mention them in one breath and to compare their natures, is proof that their spheres touch somehow, even if only peripherally.

Since common knowledge, which knows of them all, is itself an incipient science, we may be sure that some continuity and some congruity obtains between their provinces. Some aspect of each must coincide with some aspect of some other, else nobody who pursued any one science would so much as suspect the existence of the rest.

Great as may be the aversion of learned men to one another, and comprehensive as may be their ignorance, they are not positively compelled to live in solitary confinement, and the key of their prison cells is at least in their own pocket.

George Santayana - The Life of Reason