Aristotle invented formal logic. He also came up with the idea of separate
sciences. For him there was a close connection between logic and science,
inasmuch as he considered logic to be an instrument with which to formulate
language properly when analyzing what science involves.
The Categories and the Starting Point of Reasoning
Before we can logically demonstrate or prove something, we must have a clear
starting point for our reasoning process. For one thing we must specify the subject
matter we are discussing
the specific “kind” of thing we are dealing with.
Whenever we think of some distinct thing, we think of a subject and its
that is, of some substance and its accidents.
Aristotle proposed at least nine categories (that is, predicates) that can be
connected with a substance.
We can consider substance itself as a category, in which case a substance is a
Aristotle did not consider these categories or these classifications as artificial
creations of the mind. He thought that they were actually in existence outside the
mind and in things. Things, he thought, fell into various classifications by their
very nature because they are.
There are always predicates (categories) related to subjects (substances).
What Aristotle wants to underscore is that there is a sequence that leads to
“science.” This sequence is, first of all, the existence of things and their processes;
second, our thinking about things and their behavior; and, finally, the
transformation of our thought about things into words. Language is the instrument
for formulating scientific thought. Logic, then, is the analysis of language, the
process of reasoning, and the way language and reasoning are related to reality.
Aristotle develops a system of logic, based on the syllogism, which he defines as
a “discourse in which certain things being stated, something other than what is
stated follows of necessity from their being so.”
The first two statements are premises, which serve as evidence for the third
statement, which is conclusion.
Although Aristotle’s theory of the syllogism is an effective tool for determining
valid relationships between premises and conclusions, his aim was to provide an