This article explains different views on concepts, which are among the most fundamental constructs in cognitive science. Michael Dummett argues that nonhuman animals are not capable of full-fledged conceptual thought but only a diminished form of thought, which he calls, proto-thought. Human beings can remove themselves from the moment and can rise above the confined world of current perceptions because of their linguistic abilities. Donald Davidson, a contemporary philosopher, denies that animals are capable of conceptual thought and claim that conceptual content requires a rich inferential network. Donald Davidson made an argument against animals having conceptual thought. Davidson's original formulation of the argument begins with the claim that having a belief requires having the concept of a belief but adds that having the concept of belief requires possession of a natural language. It follows, then, that to have a belief requires facility with natural language. The characterization of the conceptual/nonconceptual distinction that is implicit in Davidson's metacognitive argument is a complex one involving a capacity for belief about beliefs, a concept of belief, and concepts of truth and falsity. Both Robert Brandom and John McDowell argued that conceptual thought requires more than a capacity for detection. They claim that conceptual thought requires the ability to appreciate the reasons that would justify a given concept's application and use, and this, in turn, is inherently a social practice that is dependent on natural language