Sub specie aeternitatis (Latin for "under the aspect of eternity")[1] is, from Baruch Spinoza onwards, an honorific expression denoting what is considered to be universally and eternally true, without any reference to or dependence upon temporal facets of reality. The Latin phrase can be rendered in English as "from the perspective of the eternal". More loosely, it is commonly used to refer to an objective (or theoretically possible alternative) point of view.
Spinoza's "eternal" perspective is reflected in his Ethics (Part V, Prop. XXIII, Scholium), where he applies Euclid's method (with the use of geometry) to philosophical inquiry, starting with God and nature, before moving to human emotions and the human intellect to reach an understanding of moral philosophy. By proceeding sub specie aeternitatis, Spinoza sought to arrive at an ethical theory that is as precise as Euclid's Elements. In the history of philosophy, this way of proceeding may be contrasted with Aristotle's. Aristotle's methodological differentiations in his "philosophy of human affairs" and his natural philosophy are grounded in the distinction between what is "better known to us" and things "better known in themselves", or what is "first for us" and what is "first by nature"[clarification needed] (discussed, for example, at Metaphysics Z.3, 1029b3–12), a distinction that is deliberately discarded by Spinoza, and also by other modern philosophers.