Ian specializes in Ancient Greek Philosophy and has substantial side interests in Contemporary Aesthetics, Epistemology and Applied Ethics.

His book-length project concerns Aristotle's conception of rationality. What is it about human thinking that distinguishes it from the sorts of thinking other animals are capable of? Of particular importance is our capacity to form beliefs. Unlike wisdom, understanding and expertise--all high-level perfections of reason--beliefs are piecemeal and fallible, yet still beyond the reach of any non-human mind. Aristotle's theory of belief, however, gets relatively little attention compared to his deductive model of science and knowledge. A serious effort at understanding it, then, can tell us what on his view distinguishes the rational from the non-rational.

Ian is also writing on ancient conceptions of knowledge and its relation to other mental states; Aristotle's response to Protagoras, both the sophist himself and his Platonic shadow; and the history and prehistory of the emotions and their place in our mental lives.