Leonardo da Vinci on animals

Iron rusts from disuse; stagnant water loses its purity and in cold weather becomes frozen; even so does inaction sap the vigor of the mind.

Simplicity is the ultimate sophistication.

Anyone who invokes authors in discussion is not using his intelligence but his memory.

Women and cats will do as they please, and men and dogs should relax and get used to the idea.

Robert A. Heinlein1907–1988Glory Road (1963)

• Men
• Women

I believe that our Heavenly Father invented man because he was disappointed in the monkey.

Mark Twain1835–1910

• Anti-God

Man [has] always assumed that he was more intelligent than dolphins because he had achieved so much-the wheel, New York, wars and so on-while all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man-for precisely the same reason.

Douglas Adams1952–2001