"The metaphysical system of Spinoza is of the type inaugurated by Parmenides. There is only one substance, "God or Nature"; nothing finite is self-subsistent. Descartes admitted three substances, God and mind and matter; it is true that, even for him, God was, in a sense, more substantial than mind and matter, since He had created them. But except in relation to God's omnipotence, mind and matter were two independent substances, defined, respectively, by the attributes of thought and extension. Spinoza would have none of this. For him, thought and extension were both attributes of God. God also has an infinite number of other attributes, since He must be in every respect infinite; but these others are unknown to us. Individual souls and separate pieces of matter are, for Spinoza, adjectival; they are not things, but merely aspects of the divine Being. There can be no such personal immortality as Christians believe in, but only that impersonal sort that consists in becoming more and more with God. Finite things are defined by their boundaries, physical or logical, that is to say, by what they are not: "all determination is negation." There can only be one Being who is wholly positive, and He must be absolutely infinite. Hence Spinoza is led to a complete and undiluted pantheism."