Spinoza claims that the things that make up the universe, including human beings, are God's "modes". This means that everything is, in some sense, dependent upon God. The nature of this dependence is disputed. Some scholars say that the modes are properties) of God in the traditional sense. Others say that modes are effects of God. Either way, the modes are also logically dependent on God's essence, in this sense: everything that happens follows from the nature of God, just as it follows from the nature of a triangle that its angles are equal to two right angles. Since God had to exist with the nature that he has, nothing that has happened could have been avoided; and, if God has fixed a particular fate for a particular mode, there is no escaping it.
Spinoza attacks several CartesianCartesian_dualism) positions: (1) that the mind and body are distinct substances that can affect one another; (2) that we know our minds better than we know our bodies; (3) that our senses may be trusted; (4) that despite being created by God we can make mistakes, namely, when we affirm, of our own free will, an idea that is not clear and distinct. Spinoza denies each of Descartes's points. Regarding (1), Spinoza argues that the mind and the body are a single thing) that is being thought of in two different ways.