Written by one of today's most creative and innovativephilosophers, Ruth Garrett Millikan, this book examinesbasic empirical concepts; how they are acquired, how theyfunction, and how they have been misrepresented in the traditional philosophical literature. In a radical departure fromcurrent philosophical and psychological theories of concepts,this book provides the first in-depth discussion on the psychological act of reidentification. It will be of interest to abroad range of students of philosophy, especially those interested in the application of evolutionary theory to analyticphilosophy.