The mind as a complex matter

In this thesis, we will investigate how the notion of complexity and, especially, that of computational complexity, can be applied to philosophically rich problem in order to get a better understanding of them or a straight redefinition. Differently from other more comprehensive work on complexity like that from Bruce Edmonds (1995), here we will not propose a history of said notion, or an exhaustive review. Instead, our target will be that of sticking with a notion of complexity, namely computational complexity, and proceed through comparisons and applications so that the elements of interest can emerge. This will be done with the goal of finding a philosophical role for computational complexity and to verify the hypothesis that this particular notion of complexity is particularly well suited to evaluate the plausibility of all kind of theories. The thesis will be ideally divided in three separate sections. In the first we will analyse the philosophical aspects of complexity. We will see what kind of features does it have as a notion and why is it important for philosophy of mind and cognitive science. In the second section, we will look at three different philosophical applications of computational complexity and of the tractable cognition thesis. The third section will be dedicated to more cognitivistic application. The rationale behind this section is to look at how computational complexity improves the understanding of cognitive capacities and features of cognitive systems that have high philosophical relevance. This allows to both see how the role of plausibility notion is fulfilled on the part of computational complexity both on the upper bound and lower bound of cognition.