Sun 13 Nov, 2011 11:12 pm
It's based on the Law of Non-Contradiction (436c), but that would imply that there could easily be more than three parts of the soul (i.e. say you have just come to the end of a delicious dinner and have one sip of water [D] and one bite of food [E] left; you want to consume both, but eating either would fill you up and you are conflicted [(D & ~E) & (~D & E)], which would imply that the appetitive part of the soul could be divided into two parts, resulting in a four-part soul). Knowing this, is there any way Plato's Tripartite Theory of the Soul can be defended?
Depends on what you call defensible. If we accept Plato's PNC, then there will be distinct parts of the soul and of the state, each of which is related to its Idea, or to a specific universal concept. This much is logically coherent. When he decides that there are three parts, one could ask why not four or five? His choice appears to have been made on the number he thinks common sense will support. This is a pragmatic consideration, not one based in deduction. Common sense is different today than it was in ancient Athens, so we could pick a different number of divisions.