Ética, Parte I, Proposición 5
There cannot exist in the universe two or more substances having the same nature or attribute.
Demostración
If several distinct substances be granted, they must be distinguished one from the other, either by the difference of their attributes, or by the difference of their modifications (Prop. iv.). If only by the difference of their attributes, it will be granted that there cannot be more than one with an identical attribute. If by the difference of their modifications--as substance is naturally prior to its modifications (Prop. i.),--it follows that setting the modifications aside, and considering substance in itself, that is truly, (Deff. iii. and vi.), there cannot be conceived one substance different from another,--that is (by Prop. iv.), there cannot be granted several substances, but one substance only. Q.E.D.
Benedict de Spinoza, The Ethics (Ethica Ordine Geometrico Demonstrata), traducido del latín por R. H. M. Elwes.
Publicado por primera vez en The Chief Works of Benedict de Spinoza, vol. II (London: George Bell and Sons, 1884).
Esta traducción es de dominio público en Estados Unidos, donde se publicó en 1884, y en cualquier lugar donde el plazo de derechos de autor sea la vida del autor más 100 años o menos; su traductor murió en 1892.
La división en unidades, los títulos y la ubicación de las notas son de este sitio.
Texto digital: Project Gutenberg eBook #3800