This chapter discusses whether Heidegger’s holism – roughly, the view that the meaning of the parts (entities) depends on the whole (the world) – entails a vicious relativism. I argue that Heidegger is a holist because he is committed to both object externalism (the view that intentional states depend on environmental objects) and social externalism (the view that intentional states depend on other people). Whether his holism entails relativism depends on how we understand these two commitments. Discussing recent interpretations of Heidegger’s holism (Lafont, Dreyfus, Okrent, Carman), I argue that Heidegger’s holism entails a form of relativism only if we take his social externalism to be a function of social conventions. I then go on to challenge that this is the case by arguing that Heidegger is an open-ended social externalist according to whom intentional states do not depend solely on our relation to social conventions (or any other particular social formation such as language or tradition) but on our on-going social interaction broadly construed.