Ethics, Part III, Proposition 6
Everything, in so far as it is in itself, endeavours to persist in its own being.
Proof
Individual things are modes whereby the attributes of God are expressed in a given determinate manner (I. xxv. Coroll.); that is, (I. xxxiv.), they are things which express in a given determinate manner the power of God, whereby God is and acts; now no thing contains in itself anything whereby it can be destroyed, or which can take away its existence (III. iv.); but contrariwise it is opposed to all that could take away its existence (III. v.). Therefore, in so far as it can, and in so far as it is in itself, it endeavours to persist in its own being. Q.E.D.
Benedict de Spinoza, The Ethics (Ethica Ordine Geometrico Demonstrata), translated from the Latin by R. H. M. Elwes.
First published in The Chief Works of Benedict de Spinoza, vol. II (London: George Bell and Sons, 1884).
This translation is out of copyright in the United States, where it was published in 1884, and wherever the copyright term is the author's life plus 100 years or less; its translator died in 1892.
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