In a Facebook philosophy group one participant asked the others: "What are your thoughts on being a truly rational person?"
I liked my own answer so much I thought I'd reproduce it here. It is direct from the Jamesian playbook.
Rationality consists of two very different pulls: one toward the general and one toward the particular.
We always get a sense of rationality when we learn that two different-seeming things are in some respect the same. When the orbit of the moon is explained by a law that also covers the fall of an apple, or when electricity and magnetism turn out to be the same force. The rational impulse is toward the general.
On the one hand, we have a natural fear of vagueness and so of generality. We want to know the particular workings of things. "Let's be specific." That too is a rational drive. The encyclopedia is as rational a phenomenon, even as much an ideal of rationality, as the concise governing law.
A rational mind in the broadest sense can include any mind that feels either of these pulls. A rational mind in the purest sense in one that feels both of them.