This episode applies the distinction between personal and shared inquiry—developed in the previous episodes—to philosophical inquiry, arguing that philosophy is a personal affair. It sketches a picture of doing philosophy as the activity of creating an equilibrium of philosophical ideas based on personal nodes that are best described as a kind of intellectual tastes. This picture is shown to be superior to the naturalist picture of philosophy—according to which philosophy is a scientific inquiry—because it can explain why philosophers could rationally believe their theories in the face of systemic peer disagreement and why there can be a sense of philosophical progress in spite of such disagreement.
This episode sets the stage for the next one by drawing and explaining a distinction in epistemic rationality. It argues that rationality is always a structural feature. When inquiry is personal—such as inquiry into matters of taste—this structure is internal to the individual and it is characterized by certain personal nodes, such as aesthetic predilections or fundamental moral convictions, whereas when inquiry is shared—such as scientific inquiry—we aim toward an interpersonal structure that is purely based on shareable evidence and lacks these personal nodes. This difference in rationality sheds light on differences in the mechanics of testimony and peer disagreement that will be very important for explaining why philosophy is a personal inquiry.
Tom Kaspers 