Department of

Rule I reached its final form in the Second Edition, where it was also transformated from an Hypothesis to a Rule. The Rule later became known as the "vera causa" principle. The final version reads:

The revisions:

	English
Principia (1687)	Hypoth. I. No more causes of natural things should be admitted than are both true and sufficient to explain their phenomena. For Nature is simple and does not indulge in the luxury of superfluous causes.
1690s Revisions	Ei1: A middle sentence is added: Rule I. As the philosophers say: Nature does nothing in vain, and more causes are in vain when fewer suffice.
Principia (1713)	Rule I. No more causes of natural things should be admitted than are both true and sufficient to explain their phenomena. As the philosophers say: Nature does nothing in vain, and more causes are in vain when fewer suffice. For Nature is simple and does not indulge in the luxury of superfluous causes.
1710s Revisions	No change
Principia (1727)	No change.

University of Pittsburgh · Faculty of Arts and Sciences