“You ask, my friend, what am I doing today? That which I did yesterday. Again you ask, what am I planning to do tomorrow? That which I am doing today. Our Plato has persuaded me that I would in the end accomplish most if I always did the same thing. And this is perfectly right. Assuredly a man who pursues everything achieves nothing; for many obstruct one, wheras one serves and unites many.
He is one of a crowd, who pursues many things; singular indeed is he who pursues one. It is the mark of an immature and weak mind to undertake many different things at any one moment. It is also rash ambition daily to promise many things. Pythagoras teaches us that unity looks towards the good, but diversity towards the evil. Just as when the natural force in the liver or the vital force in the heart is drawn apart into two, and as a consequence is weakened, so the conscious force in the brain does not equip us for diverse actions. Besides, each man carries out most effciently what each is best suited for by nature. One accords with one, therefore one is necessary, plurality brings confusion; one , I say because it is in itself pure, and more appropriate than anything else for the man who acts.
Finally, if God is always the same and sets the same things in motion, a man is further away from God the more inclined he is to different things.”
10th December 1476
From “The Letters of Marsilio Ficino” translated by the language department of the School of Economic Science Volume 2.