Aristotle was the Greek philosopher who described the rhetorical triangle or the three types of appeals or otherwise known as the three proofs. These are known as ethos, logos and pathos.
ETHOS- this is the Greek word for character. It refers to how trustworthy or credible the speaker or writer is and how knowledgeable he or she is concerning a specific subject matter.
PATHOS- is the Greek word for suffering or experience. It refers to the emotions, interests, sympathies, and or imagination.
and lastly, LOGOS- the Greek word for word. It refers to the clarity of the claim, logic and the effectiveness of its supporting details or evidence.