Ptolemy quotes

Ptolemy was a Greco-Egyptian mathematician, astronomer, and geographer, famous for his influential works in science. His most notable achievements include the Almagest, which shaped astronomical knowledge for centuries. He also made significant contributions to the fields of geography and optics. Here are 10 of his quotes:

There are three classes of friendship and enmity, since men are so disposed to one another either by preference or by need or through pleasure and pain.

Ptolemy

The length of life takes the leading place among inquiries about events following birth.

Ptolemy

We consider it a good principle to explain the phenomena by the simplest hypothesis possible.

Ptolemy

I know that I am mortal by nature and ephemeral, but when I trace at my pleasure the windings to and fro of the heavenly bodies, I no longer touch earth with my feet. I stand in the presence of Zeus himself and take my fill of ambrosia.

Ptolemy

Everything that is hard to attain is easily assailed by the generality of men.

Ptolemy

To give here an elaborate account of Pappus would be to create a false impression. His work is only the last convulsive effort of Greek geometry which was now nearly dead and was never effectually revived. It is not so with Ptolemy or Diophantus. The trigonometry of the former is the foundation of a new study which was handed on to other nations indeed but which has thenceforth a continuous history of progress.

Ptolemy

He left in his Optics, the earliest surviving table of angles of refraction from air to water. ...This table, quoted and requoted until modern times, has been admired... A closer glance at it, however, suggests that there was less experimentation involved in it than originally was thought, for the values of the angles of refraction form an arithmetic progression of second order... As in other portions of Greek Science, confidence in mathematics was here greater than that in the evidence of the senses, although the value corresponding to 60° agrees remarkably well with experience.

Ptolemy

Ptolemy's Geography is the only book on cartography to have survived from the classical period and one of the most influential scientific works of all time.

Ptolemy

Claudius Ptolemy's great contribution to astronomy was his famous work the Almagest, which presented formally the astronomical theories of the day that had evolved from the great debates within the different Greek philosophical schools. Claudius Ptolemy freely admitted that he had contributed little original research to the treatise but rather had based his conclusions principally on the work of Hipparchus. ...Ptolemy did not claim that his cosmological model described the actual conditions. It simply reproduced geometrically the observed motions of the known heavenly bodies and enabled their positions to be easily predicted for any particular time. ... Ironically, even when Copernicus' heliocentric theory had replaced the Ptolemaic system, many astronomers used Ptolemy's model to predict the motion of the planets, since its intricate calculations produced more accurate values.

Ptolemy