Even though apes are the only nonhuman creatures able to learn human language, no ape has ever used its human language skills to ask such philosophical questions as, “How am I different from all other creatures?” Therefore, philosophical thought is unique to humans.
Conclusion (Therefore)
Philosophical thought is unique to humans.
Evidence
Apes are able to learn human language, but no ape has ever used its human language skills to ask philosophical questions such as, “How am I different from all other creatures?”
Evaluate
This argument assumes that the way to detect philosophical thought is by the expression of philosophical questions in human language. In other words, the author takes the fact that apes, although capable of learning human language, have not asked philosophical questions as sufficient evidence that such thought is exclusively human.
Goal
Look for an answer that fills the gap between the evidence and the conclusion by assuming that philosophical thought must be expressed in human language. If philosophical thought could be expressed in some other way, the absence of philosophical questions in apes would not necessarily mean they lack philosophical thought.