Baruch Spinoza (1632–1677) believed in
Like Descartes, Spinoza wrestled with the idea of Substance.
Descartes called the infinite substance God; Spinoza called it Nature. His belief that God is Nature and that nature is one substance that can shape-shift into various forms that he called
Pantheism is the belief that God is Nature, in everything and around us all the time. Baruch Spinoza's brand of pantheism captured the worst of all possible spiritual beliefs. He denied the existence of the soul after death, yet the world was governed by predestination.
Like Descartes, Spinoza eschewed the passions, believing that they got in the way of inner peace. He believed in acceptance of your lot in life, and that you are part (however inconsequential) of a cosmic Big Picture (however impersonal), and that you are a happy anonymous mode among a myriad of other modes should provide at least a modicum of serenity. Needless to say, many disagreed with this philosophy.