A bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements, but not with a corresponding degree of strength, though it is deficient only in the power of maintaining equilibrium. We may therefore say that such an instrument constructed by man is lacking in nothing except the life of the bird, and this life must needs be supplied from that of man.

Common Sense is that which judges the things given to it by other senses.

Those who, in debate, appeal to their qualifications, argue from memory, not from understanding.

O sleepers! what a thing is slumber! Sleep resembles death. Ah, why then dost thou not work in such wise as that after death thou mayst retain a resemblance to perfect life, when, during life, thou art in sleep so like to the hapless dead?

Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.

The motions of men must be such as suggest their dignity or their baseness.

Any color is more distinctly seen when opposed to its contrary: thus, black on white, blear near yellow, green near red, and so on.