In early philosophies of psychology and metaphysics, conatus (; 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.