This chapter focuses on one historically important approach to computationalism about thought. According to "the classical computational theory of mind" (CTM), thinking involves the algorithmic manipulation of mental symbols. The chapter reviews CTM and the related language of thought (LOT) position, urging that the orthodox position, associated with the groundbreaking work of Jerry Fodor, has failed to specify a key component: the notion of a mental symbol. It clarifies the notion of a LOT symbol and explores an approach different from the orthodox, Fodorian LOT/CTM. The LOT position is a leading approach to the computational nature of thought. A key feature of LOT is that its mental representations have a combinatorial syntax. A representational system has a combinatorial syntax when it employs a finite store of atomic representations, which can be combined to form compound representations, which can then be combined to form further compound representations.