デカルトの自然主義的性格--第三省察における「観念」

Abstract

In the Third Meditation, as you know, Descartes intends to prove the existence of God. For this purpose, he analyzes various 'ideas' which are in our minds. In this case, according to the demonstration in the First and Second Meditation, the existence of external world hasn't yet been established. After he has proved the existence and veracity of God, Descartes establishes his natural philosophy (or physics). Consequently, the argument in the Third Meditation apparently doesn't include the logic of natural philosophy and is extremely metaphysical. It is also the term 'idea' and several concepts concerning it, as you know, that play an important role in the proof of God's existence. Therefore the term 'idea' used in this context may be metaphysical in principle. In The World and The Dioptrics (they were written before the Meditations and the Principles), however, Descartes frequently used the term 'idea' in explaining how we perceive objects in the external world. Doesn't the use of the term 'idea' in this context of natural philosophy influence to a large degree the metaphysical demonstration in the Third Meditation? In other words, does Descartes utterly remove the use of it in the context of natural philosophy from the argument proving the existence of God? The aim of this paper is to clarify the relationship between Descartes's metaphysics and his natural philosophy, especially how the logic of natural philosophy enters the metaphysical demonstration of the existence and veracity of God. In order to achieve this aim, I will examine carefully how Descartes uses the term 'idea' in demonstrating the existence of God. Needless to say, Descartes doesn't declare the structure of this metaphysical argument to possess physical logic. This paper will suggest, however, that the logic of his natural philosophy is latent in the metaphysical argument of the Third Meditation.