Proof.—The effort for self—preservation is the essence of a thing (III. Therefore no virtue, &c.
 Baruch Spinoza, Ethics (1677). copy citation

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Author Baruch Spinoza
Source Ethics
Topic virtue effort
Date 1677
Language English
Reference
Note Translated by R. H. M. Elwes
Weblink http://www.gutenberg.org/files/3800/3800-h/3800-h.htm

Context

“No virtue can be conceived as prior to this endeavour to preserve one's own being.
vii.) ; therefore, if any virtue could be conceived as prior thereto, the essence of a thing would have to be conceived as prior to itself, which is obviously absurd. Proof.—The effort for self—preservation is the essence of a thing (III. Therefore no virtue, &c. Q.E.D.
Corollary.—The effort for self—preservation is the first and only foundation of virtue. For prior to this principle nothing can be conceived, and without it no virtue can be conceived.
PROP. XXIII.” source