The philosophical significance of the De Se

Inspired by Castañeda, Perry and Lewis argued that, among singular thoughts in general, thoughts about oneself ‘as oneself’–first-personal thoughts, which Lewis aptly called de se–call for special treatment: we need to abandon one of two traditional assumptions on the contents needed to provide rationalizing explanations, their shareability or their absoluteness. Their arguments have been very influential; one might take them as establishing a new ‘effect’–new philosophical evidence in need of being accounted for. This is questioned by the skeptical arguments in recent work by Cappelen & Dever and Magidor, along lines that a few discrepant voices had already announced earlier. Skeptics content that the evidence does not really call for revising traditional theories of content. I will discuss their challenges–first and foremost, concerning action explanations–aiming to make the case that the ‘De Se effect’ is no illusion: de se attitudes require us to revise one of the two tenets of traditional views.