Expound and evaluate Descartes' argument that since I am imperfect I could not have within me the idea of a perfect being unless it were placed in my mind by God.

We can look at the idea of the 'Causal Reality Principle' where 'there must be at least as much reality in the cause as in the effect of that cause'. We can see for there to be an order there has to be a first orderer, for causation a first cause and for a movement a prime mover. How we link this to God is to say that to have an idea of God there is only one possible cause for this idea and that is God himself - he placed the idea in our minds. It is only God that contains enough 'formal reality' to cause the idea with that much 'objective reality'.

We can see therefore that this 'Causal Reality Principle' seems plausible, for example, a stove burning at less than 100 degrees centigrade will never heat water to the boiling point. We can see therefore that there can be nothing in an effect which was not present 'formally' (literally) or 'eminently' (in a higher form) in the cause. By looking at it in terms of perfection we can see that for any given effect e, if e has a certain degree of perfection, there must be at least as much perfection in the cause of e as there is in e. This doesn't just happen in physical effects, i.e. the example of the stove, but Descartes' also believes it happens in ideas and to the 'representative' or 'objective' reality in them.

If we accept this premise of the 'Causal Reality Principle' (something that Hume says is impossible) then it follows that something caused Descartes' idea of God. In order to get to what the cause must be, Descartes also has to assume another unexpressed premise that the cause of anything must be at least as perfect as the effect. If something less perfect were to produce what is more perfect, we would be getting 'more reality' out of 'less reality'. That in turn would be a violation of 'nothing comes from nothing'. It was Descartes who said that he knew that 'ideas are in me like copies which can fall short of perfection of the objects from which they are derived, but cannot contain anything greater or more perfect'.

Given this, it follows that there must be a cause of Descartes' idea of God, and whatever that cause might be, it must have in it at least as much 'perfection' as is found in his idea of God. Descartes first asks himself if he (as a 'thinking thing') could be the cause of his idea of God. He answers 'no' because the idea of God has within it the thought of infinite perfection. Descartes calls that which is 'real' in thought, i.e. real as an idea in a mind, 'objective reality', by which he means 'real' as an object of thought; that which is real in the more or less ordinary sense of the word, i.e. real apart from being an idea in some mind or another, he calls 'formal reality'. However when he considers himself 'objectively' i.e. as an object of his own thinking, what he is thinking of has less than infinite perfection, and is in fact imperfect in the sense that all he knows at present is the existence of himself as a mind. Consequently if he were to have created his own idea of God, more perfection (even though it is only the thought of perfection in an idea), would have come from less, but by his premise that is impossible. So whatever the cause is it is not him. Next, he considers what could have created an idea of an infinitely perfect being. Clearly by the above premises anything that could do so must have within it at least as much perfection as the idea of an infinitely perfect being.

Only two possibilities could contain infinite perfection, 1. Something which has within itself 'objectively' infinite perfection (i.e. the idea or thought of infinite perfection), namely another idea of an infinitely perfect being, or 2. Something which 'formally' contains infinite perfection itself (i.e. that which really is infinitely perfect), namely an infinitely perfect being. If it is the first possibility, then Descartes' idea of an infinitely perfect being would have been created by another mind's idea of an infinitely perfect being. This maybe true due to the fact that most of us get our ideas of God from our teachers and parents. Though, some critics have pointed out that those who grew up in the barbarous societies, such as the Hurons in Canada, lacked the idea. Still, it doesn't however solve the problem, because we still need a cause for these other mind's ideas of God. We could arrange all the ideas of God in a cause and effect series, the first idea caused the second, which caused the third, which caused the forth and so on, but what caused the first idea of God? Certainly that couldn't be another idea of God (because this is the first idea) so the only possibility is the second alternative, that it was caused by a being which really does have in it 'formally infinite' perfection, i.e. God. Consequently God must exist in order for Descartes' idea of God. We couldn't have placed the idea of God in our own minds because we are finite and we couldn't get the idea of the infinite in us unless something infinite put it there, i.e. God.

It could be argued however, that Descartes assumes that his idea of perfection is itself perfect. If there was a flaw in his idea then surely it could have been caused by something less than perfect i.e. Descartes himself and thus would not prove the existence of God. In relation to this, it could be argued that the argument implies that everyone's ideas of a perfect being must have all come from the same source. However aren't people's ideas over time and history different? A further attack is one that people do have ideas that are themselves in some way perfect e.g. having an idea of a perfectly round circle- the idea cannot be false as it is relating to and describing an aspect of perfection. This idea however does not prove the existence of something; it merely shows that it is possible for an imperfect being to hold a concept of perfection. If it is possible for one to hold an idea of a perfect circle, but still be imperfect then surly you are capable of holding a concept of a perfect being whilst being imperfect yourself.