Abstract: Both McDowell and Brandom claim their own views on empiricism stem from Sellars’ London lectures. However, the former insists that the reformed concept " experience” plays an indispensible role of justification in epistemology, while the later argues that experience has only a causal role with the result that there is no need to introduce it into the picture of empirical knowledge. The London lectures do not mention the justificatory role of experience, and only include the argument of observation reports justifying the empirical knowledge expressed by their contents. Observation reports could be verbal utterances as well as the perceptual experiences which have both propositional and descriptive contents, they are essentially a certain thought occur to one in a certain context and manner. And, for this reason, experiences could play a role of justification. It could be argued, in this way, that the Brandon’s picture of empirical knowledge does not clash with the McDowell’s. Moreover, besides the forces of causality and justification, it could also be found in the three persons’ arguments the third force of building empirical knowledge, the historical force.