Confusions arise when "stable" is equated with "foundational". Spurred on by the image of a house's foundation, it is tempting to think that something provides effective support to the extent that it is rigid and stable. We argue that when considering the role of perception in grounding our concepts, exactly the opposite is true. Our perceptual system supports our ability to acquire new concepts by being flexibly tuned to these concepts. Whereas the concepts that we learn are certainly influenced by our perceptual representations, we will argue that these perceptual representations are also influenced by the learned concepts. In keeping with one of the central themes of this book, behavioral adaptability is completely consistent with representationalism. In fact, the most straight-forward account of our experimental results is that concept learning can produce changes in perceptual representations, the "vocabulary" of perceptual features, that are used by subsequent tasks.