Consider telos in terms of "purpose" as it pertains to the writer, speaker, or debater. Consider how the writer or speaker arouses desire. Logos. Logical Appeal You can consider logos to be "logic," because anything logical "makes sense"; it is reasonable. Anything that appeals logically to the mind is able to convince us of its truth. For example, if I were to argue that two angles of a triangle add up to less than 180 degrees, you would call me insane (unless you were trying to prove me wrong). But since this argument uses logic, it is known as a "logical appeal." It makes sense because it follows from the definitions of angle addition and 360 degrees. This means that I have used logos to convince you that I am not insane. In conclusion, logos is defined as "logical appeal;" an argument based on reason and evidence that causes someone to believe what is being said. Good arguments always use both logic and logos.