Susan Schneider interviewed by Richard Marshall in 3:AM Magazine:
3:AM: You’ve been bold in asserting that the Fodorian Language of Thought program and the related computational theory of mind theory have three major problems that unless solved renders them obsolete. Before saying what these problems are can you sketch out the theories and what they’re supposed to be explaining?
SS: The computational paradigm in cognitive science aims to provide a complete scientific account of our mental lives, from the mechanisms underlying our memory and attention to the computations of the singular neuron. The Language of Thought program (LOT) is one of two leading positions on the computational nature of thought, the other being a neural network based approach advanced by (inter alia) philosophers Paul and Patricia Churchland.
According to LOT, humans and even non-human animals think in a lingua mentis, an inner mental language that is not equivalent to any natural language. This mental language is computational in the sense that thinking is regarded as the algorithmic manipulation of mental symbols, where the ultimate algorithm is to be specified by research in the different fields of cognitive science. The “Computational Theory of Mind” holds that part or all of the brain is computational in this algorithmic sense. In my book on LOT, I urged that both approaches are insightful; the brain is probably a hybrid system — being both a symbol processing engine, and having neural networks. In particular, deliberative, conscious thought is symbolic, but it is implemented by neural networks.
3:AM: The problems are about computationality, symbols and Frege aren’t they. Can you say what’s wrong?
SS: Sure. Several problems have plagued the LOT approach for years: First, LOT’s chief philosophical architect, Jerry Fodor, has argued the cognitive mind is likely non-computational. Fodor calls the system responsible for our ability to integrate material across sensory divides and generate complex, creative thoughts “the central system.” Believe it or not, Fodor holds that the brain’s “central system” will likely defy computational explanation. One of his longstanding worries is that the computations in the central system are not feasibly computed within real time. For if the mind truly is computational in a classical sense, when one makes a decision one would never be able to determine what is relevant to what. For the central system would need to walk through every belief in its database, asking if each item was relevant. Fodor concludes from this that the central system is likely non-computational. Shockingly, he recommends that cognitive science stop working on cognition.