In early philosophies of psychology and metaphysics, conatus (/koʊˈneɪtəs/;Latin for "effort; endeavor; impulse, inclination, tendency; undertaking; striving") is an innate inclination of a thing to continue to exist and enhance itself. This "thing" may be mind, matter or a combination of both. Over the millennia, many different definitions and treatments have been formulated. Seventeenth-century philosophers René Descartes, Baruch Spinoza, Gottfried Leibniz, and Thomas Hobbes made important contributions. The conatus may refer to the instinctive "will to live" of living organisms or to various metaphysical theories of motion and inertia. Often the concept is associated with God's will in a pantheist view of Nature. The concept may be broken up into separate definitions for the mind and body and split when discussing centrifugal force and inertia.
The history of the term conatus is that of a series of subtle tweaks in meaning and clarifications of scope developed over the course of two and a half millennia. Successive philosophers to adopt the term put their own personal twist on the concept, each developing the term differently such that it now has no accepted definition. The earliest authors to discuss conatus wrote primarily in Latin, basing their usage on ancient Greek concepts. These thinkers therefore used "conatus" not only as a technical term but as a common word and in a general sense. In archaic texts, the more technical usage is difficult to discern from the more common one, and they are also hard to differentiate in translation. In English translations, the term is italicized when used in the technical sense or translated and followed by conatus in brackets. Today, conatus is rarely used in the technical sense, since modern physics uses concepts such as inertia and conservation of momentum that have superseded it. It has, however, been a notable influence on nineteenth- and twentieth-century thinkers such as Arthur Schopenhauer, Friedrich Nietzsche, and Louis Dumont.