But if we must grant that both heat and cold are substances, let us proceed a little farther in our discourse, and enquire what sort of substance is cold, and what is its first principle and nature.They then who affirm that there are certain irregular triangular figures in our body, and tell us also that shuddering, trembling, and quivering, and whatever else we suffer of the same nature, proceed from the roughness of those figures, if they mistake in the parts, nevertheless derive the beginning from whence they ought. For we ought to begin the question—as it were from Vesta— from the substance of all things. By which it chiefly appears wherein a philosopher differs from a physician, a husbandman, or a piper. For it is sufficient for these to contemplate the last causes. For if the consideration of the nearest causes of the affection go no farther than to find that the cause of a fever is intenseness of heat, or the lighting of some humor where it ought not to be, that the cause of blasting is the scorching heat of the sun after rain, and that the cause why pipes give a bass sound is the inclination of the pipes or the bringing them near one to another; this is enough for the artist to know in reference to his business. But when a philosopher for contemplation’s sake scrutinizes into the truth, the knowledge of remote causes is not the end but the beginning of his proceeding in search of the first and ultimate causes. Wherefore Plato and Democritus, enquiring after the cause of heat and gravity, did not stop at the consideration of earth and fire, but bringing things perceptible to sense to beginnings intelligible only by the mind, they went on even to the smallest, as it were the seeds of what they sought for.