1) According to Descartes, there are three degrees of formal reality. There are infinite substances, finite substance, and characters (properties). The formal reality is what we would call actually existing things. The objective reality of a thing is what we can imagine that thing to have. The objective reality of objects is contained in the idea of said objects. Descartes basic claim is that we cannot have an idea of X that is greater than the X we have experienced in actual existence. His example is that the idea of a stone cannot exist in him unless he has had a formal experience with a stone that has at least as much reality as his conception of the stone.
2) In this argument, he is talking about formal reality in relation to cause and effect. He is referring to the fact that less-perfect beings cannot create more perfect beings (as another translation says). This is different than the first argument because it is talking about the relations among different degrees of formal reality, whereas p1 was talking about the relation between formal reality and objective reality. This part of his argument is important, because it has to be proved that there has to be a supreme being (formal reality) that created everything beneath it in succession.
3) For Descartes a things nature is contained in the thing, and is that which is unchanging, or that of which we can be clearly aware. A things nature is not invented by our minds and is dependent of our thinkings’ about the object or abstract object in question. This is important because it is a form of an ontological argument for Descartes. For him, God exists just based on this definition as well as his previous two principles from meditation 3. This is important because it includes the idea that God necessarily exists based on the