As defined by psychologists, learning is "the modification of behavior as the result of experience." The problem with this definition is that it leaves the term "experience" undefined. The major contributors to early childhood education theory and practice each had his or her own conception of the process of acquiring knowledge. The philosophers were most concerned with the "What" of experience, while the practitioners were primarily concerned with the "How" of experience--with the process of learning itself. Finally, the theorists and researchers were preoccupied with the "Why" of experience and learning. Brought together, these ideas afford a comprehensive picture of the many different modes of learning young children employ in learning about themselves and their world. (Contains 2 endnotes.)