Doubt must be no more than vigilance, otherwise it can become dangerous. - Georg Christoph Lichtenberg

Es difícil que en el mundo haya mercancía más singular que los libros. Son impresos, vendidos, encuadernados, reseñados y a veces hasta escritos por gente que no los entiende.

There is no more important rule of conduct in the world than this: attach yourself as much as you can to people who are abler than you and yet not so very different that you cannot understand them.

Diogenes, filthily attired, paced across the splendid carpets in Plato's dwelling. Thus, said he, do I trample on the pride of Plato. Yes, Plato replied, but only with another kind of pride.