Spinozism (also spelled Spinoza-ism or Spinozaism) is the monist philosophical system of Baruch Spinoza which defines "God" as a singular self-subsistent substance, with both matter and thought being attributes of such.
In a letter to Henry Oldenburg Spinoza wrote: "as to the view of certain people that I identify god with nature (taken as a kind of mass or corporeal matter), they are quite mistaken". For Spinoza, our universe (cosmos) is a mode under two attributes of Thought and Extension. God has infinitely many other attributes which are not present in our world. According to German philosopher Karl Jaspers, when Spinoza wrote "Deus sive Natura" (God or Nature) Spinoza meant God was Natura naturans not Natura naturata, that is, "a dynamic nature in action, growing and changing, not a passive or static thing." Jaspers believed that Spinoza, in his philosophical system, did not mean to say that God and Nature are interchangeable terms, but rather that God's transcendence was attested by his infinitely many attributes, and that two attributes known by humans, namely Thought and Extension, signified God's immanence. Even God under the attributes of thought and extension cannot be identified strictly with our world. That world is of course "divisible"; it has parts. But Spinoza insists that "no attribute of a substance can be truly conceived from which it follows that the substance can be divided" (Which means that one cannot conceive an attribute in a way that leads to division of substance), and that "a substance which is absolutely infinite is indivisible" (Ethics, Part I, Propositions 12 and 13). Following this logic, our world should be considered as a mode under two attributes of thought and extension. Therefore, the pantheist formula "One and All" would apply to Spinoza only if the "One" preserves its transcendence and the "All" were not interpreted as the totality of finite things.