Sellars's views on the Myth of the Given and the ontological status of secondary qualities, one would have thought, are well-known, even if not always well-understood. One would not have expected his Carus Lectures, then, to offer anything radically new and exciting. ground that they cover is, after all, familiar?from Empiricism and the of Mind (1956), from Philosophy and the Scientific Image of Man (1962), from The Identity Approach to the Mind-Body Problem (1965), and from the ensuing debates with Cornman (Science, Sense Impressions, and Sensa: A Reply to Cornman, 1971) and with Firth (Givenness and Explanatory Coherence, 1973). One would not really have anticipated many surprises. But one would have been wrong. Sellars's Carus Lectures, in fact, engender a sense of shock. What has become of ultimate homogeneity and the notorious Grain Argument over which so much ink has been spilled? Where is the Strong Principle of Reducibility which played such a central role in Sellars's reply to Cornman? What are we to make of the new distinction between the mind-body problem and the sensorium-body problem? And why has an ontology of absolute processes?hitherto always merely mentioned, more or less as a postscript?suddenly assumed such extraordinary prominence, becoming, in deed, the centerpiece of Sellars's lectures and evidently the linchpin upon which their story turns? Is it possible that, after more than twenty years, we had not yet quite understood what Sellars was up to all along? (What have you done with the real Wilfrid Sellars? asked a participant in a symposium at which Sellars presented portions of the Carus Lecture materials.) Yes, curiously enough, it is possible. It is even possible that Sellars has only recently fully understood just what he has been up to for more than twenty years. For while the story Sellars tells in the Carus Lectures is not, I think, radically new and different from that told in his earlier works, it is in those earlier works, I am tempted to say (Sellarsianly) only as the mature oak tree is in the acorn. One thing which it would be useful to have, then, would be some tools for seeing the acorn in the oak, and that, in fact, is what I intend to provide here. I do not, that is, propose here to engage Sellars's story critical ly, argumentatively, or evaluatively, but rather to attempt to command a clear view of what his project and his story in fact are (and, in the sense in dicated, indeed always have been)?a clear view which is a prolegomenon to