Hylozoism is the philosophical doctrine according to which all matter is alive or animated,[clarification needed][1] either in itself or as participating in the action of a superior principle, usually the world-soul (anima mundi).[2] The theory holds that matter is unified with life or spiritual activity.[3] The word is a 17th-century term formed from the Greek words ὕλη (hyle: "wood, matter") and ζωή (zoē: "life"), which was coined by the English Platonist philosopher Ralph Cudworth in 1678.