Basic Logic - Parts of a Proposition

A proposition is the point to be discussed or maintained in argument, usually stated in sentence form near the outset. The purpose of logical argument is generally to determine the truth or falsehood of a proposition.

There are three parts to any proposition:

1. The premises – i.e. facts which are already known or assumed.
2. The argument – i.e. the logical chain of reasoning that leads from the premises to the conclusion.
3. The conclusion - i.e. that which must be true if the premises are true and the argument is valid.

The conclusion must be true IF the premises are true AND the argument is valid.

The field of Logic is concerned only with the reasoning process behind the argument – logic is not concerned about the accuracy of the premises.

Note that the only objective "things" in a proposition are the premises and conclusion. The argument is a mental process and remains unseen. We can write a premise (If I stand in the rain, I'll get wet), and we can see a conclusion (I am wet), but we never actually "see" the argument itself. Although mental processes are not objectively evident in Nature, the existence of a mental process can imply that there must be an "I" that is experiencing the mental process. This was what Rene Descartes meant when he stated "I think, therefore I am."