The motions of the heavenly bodies are almost mathematical in their precision; but there is a multitude of matters, to which mathematical science is applied, which are in their nature intricate and obscure, and require that reasoning by rule should be completed by the living mind. Who would be satisfied with a navigator or engineer, who had no practice or experience whereby to carry on his scientific conclusions out of their native abstract into the concrete and the real? What is the meaning of the distrust, which is ordinarily felt, of speculators and theorists but this, that they are dead to the necessity of personal prudence and judgment to qualify and complete their logic? Science, working by itself, reaches truth in the abstract, and probability in the concrete; but what we aim at is truth in the concrete. This is true of other inferences besides mathematical. They come to no definite conclusions about matters of fact, except as they are made effectual for their purpose by the living intelligence which uses them. “All men have their price; Fabricius is a man; he has his price;” but he had not his price; how is this? Because he is more than a universal; because he falls under other universals; because universals are ever at war with each other; because what is called a universal is only a general; because what is only general does not lead to a necessary conclusion. Let us judge him by another universal. “Men have a conscience; Fabricius is a man; he has a conscience.” Until we have actual experience of Fabricius, we can only say, that, since he is a man, perhaps he will take a bribe, and perhaps he will not. “Latet dolus in generalibus;” they are arbitrary and fallacious, if we take them for more than broad views and aspects of things, serving as our notes and indications for judging of the particular, but not absolutely touching and determining facts.