The Six C's

Compatibility

Being able to go with well established facts and theories is important because a good theory is one that increases our understanding by unifying our knowledge. Hence, a theory that flies in the face of the rest of our understanding of the world may require us to lose more than we gain.

Clarity

It is the first test that a philosophy must pass. If the terms or concepts in which the philosophy is expressed are not clear, then we don't know precisely what claim is being put forth. Suppose someone says, "The only thing in life that has value is pleasure." We need to ask several questions about this philosophy, so it doesn't pass this test.

Consistency

It is the second test a philosophy needs to pass. Logical Inconsistency is one way that a philosophy flunks this test. It consists in making two assertions that couldn't both be true under any circumstances. The most common would be any claim in this form: A is true and not-A is true. They contradict each other.

Coherence

Rational Coherence is a criterion that considers how well the various parts of a philosophy "hang together". The elements of a philosophy don't neccasarily have to contradict each other, but they can fail to fit together very well. Rene Descartes argued that humans are made up of a physical body and a non extended, non physical mind. He failed to explain how such different types of substances would influence one another, however.

Comprehensiveness

We evaluate a philosophy positevely if it makes sense out of a wide range of phenomena; we evaluate it negatively if it ignores significant areas of human experience or raises more questions that it answers. A philosophy that illuminates humanity's scientific, moral, aesthetic, and religious experience is better than one that explains only science but ignores the rest of human experience.

Compelling Arguments

Whether or not you agree with it, how flashy an argument is.