is a form of computation or that the mind is a Turing machine. Computationalist theories of thought are sometimes divided into functionalist and representationalist approaches. Functionalist approaches define mental states through their causal roles but allow both external and internal events in their causal network. Thought may be seen as a form of program that can be executed in the same way by many different systems, including humans, animals, and even robots. According to one such view, whether something is a thought only depends on its role "in producing further internal states and verbal outputs". Representationalism, on the other hand, focuses on the representational features of mental states and defines thoughts as sequences of intentional mental states. In this sense, computationalism is often combined with the language of thought hypothesis by interpreting these sequences as symbols whose order is governed by syntactic rules. Various arguments have been raised against computationalism. In one sense, it seems trivial since almost any physical system can be described as executing computations and therefore as thinking. For example, it has been argued that the molecular movements in a regular wall can be understood as computing an algorithm since they are "isomorphic to the formal structure of the program" in question under the right interpretation. This would lead to the implausible conclusion that the wall is thinking. Another objection focuses on the idea that computationalism captures only some aspects of thought but is unable to account for other crucial aspects of human cognition. Types of thinking A great variety of types of thinking are discussed in the academic literature. A common approach divides them into those forms that aim at the creation of theoretical knowledge and those that aim at producing actions or correct decisions, but there is no universally accepted taxonomy summarizing all these types. Entertaining, judging, and reasoning Thinking is often identified with the act of judging. A judgment is a mental operation in which a proposition is evoked and then either affirmed or denied. It involves deciding what to believe and aims at determining whether the judged proposition is true or false. Various theories of judgment have been proposed. The traditionally dominant approach is the combination theory. It states that judgments consist in the combination of concepts. On this view, to judge that "all men are mortal" is to combine the concepts "man" and "mortal". The same concepts can be combined in different