To-day the hypothesis of Descartes has given way to that of leibnitz, who regards force as the essential property of the living being, the visible and tangible matter being only of secondary importance.
"The Mechanism of Life"
Stéphane Leduc
He was fond of comparing the two, and often quoted leibnitz: "Music is an occult exercise of the mind unconsciously performing arithmetical calculations."
"Melomaniacs"
James Huneker
The highest peak of the lunar Apennines, Huyghens, has an altitude of 18,000 feet, and the leibnitz and Doerfel Mountains, near the south pole of the moon, reach an altitude 50 per cent greater than this, and are probably the highest peaks on the moon.
"A Text-Book of Astronomy"
George C. Comstock