Much of my current research is in the philosophy of action, ancient and contemporary. In Desiring the Good: Ancient Proposals and Contemporary Theory, forthcoming from Oxford in 2017, I argue that a compelling version of the Guise of the Good must account for inter-related motivation on three levels: the largest-scale motivation to have one’s life go well, the motivation of pursuits, and the motivation of small-scale actions. I aim to show in which sense it may be true that human beings are “the measure” such that this is not a relativist proposal, but an insight about the nature of ethics. A related paper, “Plato on Hunger and Thirst,” is forthcoming in Logical Analysis and History of Philosophy 20 (2017). Another related paper, “Love and Hatred,” forthcoming in the Routledge Handbook of Love in Philosophy, is co-authored with Jens Haas.
In Belief and Truth: A Skeptic Reading of Plato (2012), paperback (2015), I trace what I take to be Socratic-skeptic intuitions in ancient epistemology. The book contains chapters on ignorance and belief in Plato, skepticism and relativism, skepticism and concepts, skeptical investigation, and Stoic epistemology. More recently, I edited as well as co-authored translation and commentary of Pyrrhonian Skepticism in Diogenes Laertius: Pyrrho (2015), a Greek-English text edition with scholarly essays. As a visiting fellow at the Hamburg Maimonides Center, I will turn to skepticism’s relation to the JTB account of knowledge.
Right now I’m devoting a considerable amount of time to Imagination and Agency, funded by the Templeton Foundation and part of a larger project on Happiness and Well-Being. I aim to clarify the Aristotelian dictum that deliberation is about the possible. Figuring out what to do involves what I call imagination-tests: envisaging oneself in possible future scenarios and interpreting one’s affective response. I argue that what I call Agency Imagination is a distinctive kind of imagination, and that being good at Agency Imagination is one component of being a good decision-maker.
A related long-term project is entitled Ignorance and Action. Discussions of ignorance and action often presuppose that we have a good grasp of what ignorance is. Against this, I argue that we can make progress in epistemology, action theory, and philosophy of law by thinking about the nature of ignorance. A first paper, co-authored with Jens Haas (who comes to this from the perspective of legal theory) and entitled “Ignorance and Investigation,” was published in (2015). We defend two premises. First, ignorance is absence of knowledge, not lack of knowledge as it is often assumed. Second, normative considerations call for a distinction between kinds of ignorance, which our wider and less pejorative notion of ignorance can accommodate.
My second book Law, Reason, and the Cosmic City (2008), paperback (2012) looks more closely at the philosophy of the most forceful ancient critics of skepticism, the Stoics. Though I think that the Stoics lose against the skeptics as far as epistemological questions are concerned, I consider their ethical outlook and conception of reason eminently interesting. More recently I turned to Stoic physics. Building on my “Sons of the Earth: Are the Stoics Metaphysical Brutes?” Phronesis (2009), I’m writing a paper entitled “The Agency of the World: Causation in Stoic Physics” (forthcoming 2017).
My first book Skepsis und Lebenspraxis (1998) was reissued as a paperback in (2015). It discusses skeptical belief, language, and action (abstract in English, pdf). In a new final chapter, I offer a sketch of research on skepticism since the book’s first publication. I also formulate 20 premises that summarize the views on skepticism that I hold today. One theme from my early work is as of yet under-represented in my publications: the skeptics’ language. The skeptics, on my reconstruction, invent a language in which one doesn’t assert anything that one doesn’t know.