It is a painful thing to say to oneself: by choosing one road I am turning my back on a thousand others. Everything is interesting; everything might be useful; everything attracts and charms a noble mind; but death is before us; mind and matter make their demands; willy-nilly we must submit and rest content as to things that time and wisdom deny us, with a glance of sympathy which is another act of our homage to the truth.
Of course, I am interested, but I would not dare to talk about them. In talking about the impact of ideas in one field on ideas in another field, one is always apt to make a fool of oneself. In these days of specialization there are too few people who have such a deep understanding of two departments of our knowledge that they do not make fools of themselves in one or the other.