Hywel Lewis’ primary thesis in The Elusive Self is that human beings are best understood as a complex integration of mental and physical states. In the first chapter, Lewis begins by recognizing the problem that this dualism has for conceiving of a constant personal identity, noting that a dualistic emphasis on sentient experience inherently raises questions of worth and significance. He further posits that dualism is largely self-evident, because it is based primarily on experience (p. 8). In a recurring example, Lewis suggests that even when there is a physical cause of pain, pain itself has no observable character; it is an aspect of personal experience. Similarly, thoughts and intentions are elements of experience rather than of physical observance. Even if one is able to tell what a friend is thinking by a particular look upon his face, one is not able to know the friends’ thoughts in the same way that she can know her own thoughts.
Lewis concurrently maintains in chapter 3, that there is a subject, or self, or soul of an individual which “remains constant and is uniquely involved in all the flow of our mental states or experience” (p. 40). This contention leads to another philosophical problem concerning the relation of this constant self to the states of the interior mind. Lewis maintains that the self is an entity over and above transient mental states though it is not detached from them. Here again, Lewis turns to the example of pain to clarify his contention. Pain relates to the self in a way that hair does not; pain cannot be separated from the perception of the self, whereas hair, when cut, can be.
This leads to a further question of how one can know an abiding, constant self. Lewis modifies Kant’s position, suggesting that while the self, as subject, can never become completely known as an object—leaving it ultimately elusive and mysterious—some knowledge of the constant self can be known in a non-comprehensive fashion. Lewis maintains that this admittedly limited knowledge of self arrives through introspection, personal experience, and personal memory.
According to Lewis’ strict definition of memory, humans only remember what is personally experienced or observed. He notes the significant weight of eye-witness testimony in courtrooms as a practical indication of the importance placed on the memory of personal experience. Lewis maintains that when a person remembers, they recall something in its fullness as an event with which they were involved. This fullness includes the individual’s awareness of their self in that instant; that is, they recall that they were the one who had this particular experience. Then, by linking together remembrances of self-experiences, a picture of a continued self emerges.
In the final chapters, Lewis utilizes a number of extreme test-cases (one such being the hemispherectomy of a brain that is then functionally placed into two separate bodies) as well as other philosophical works to hone and nuance his primary thesis. Ultimately, The Elusive Self is an impassioned defense of a dualist sense of continued self-identity, which then sets the stage for the final of Lewis’ publications based on the Gifford Lecture series, Freedom and Alienation, in which Lewis examines the implications of his dualist conception on morality, personal relationships, and religion.