There is no real moral center for any of the major characters in John Barth’s The End of the Road. Those who begin by believing that they are in secure possession of such an unshakable core of moral certitude—most notably, Joe Morgan and his wife, Rennie—are forced to accept that they have deluded themselves, first in claiming that their philosophy offers a coherent view and response to the world, and second when it is made clear that they do not, in fact, fully embrace their own philosophy. In effect, they are living a lie, and it turns out to be a lie that is not even a useful one. This realization destroys them. In the case of Rennie, she is literally destroyed.

For the Doctor and especially for his patient, Jacob Horner, there is not even the pretense of an overriding moral philosophy to guide their actions and shape their perceptions of the world. Things simply are, and the Doctor quotes, without attribution, the philosopher Ludwig Wittgenstein: “The world is everything that is the case.” The world, including human existence, must be accepted as it is, in all its conflicting confusion. There is no way to fashion it into an understandable unity. In this sense, both the Doctor and Horner are existentialists, accepting the essential absurdity of their situation and dealing with it by fashioning their own interpretations and even identities—interpretations and identities that are arbitrary and frequently changed. In the end, however, the tactics and response of existentialism prove as impractical as the moral absolutism espoused by Joe Morgan.

Ultimately, The End of the Road is concerned with two basic questions of identity and meaning: Who am I? What am I to do? Neither question is answered, and Barth’s unspoken but inescapable conclusion is that there are no answers. The novel introduces the theme of identity and meaning in its opening sentence: “In a sense, I am Jacob Horner,” writes the narrator, and throughout The End of the Road the sense of Jacob’s reality—indeed, the reality of all of the characters—constantly shifts and changes. Jacob is encouraged in his mutability by the Doctor’s highly idiosyncratic cures, most notable of which is mythotherapy, which demands the creation of a series of outward personalities totally unrelated to any inner condition. The point is for Jacob to continue acting in order to avoid the state of paralysis in which the Doctor initially finds him. Choice is essential, even if it is meaningless. As the Doctor advises Jacob, “If the alternatives are side by side, choose the one on the left; if they’re consecutive in time, choose the earlier. If neither of these applies, choose the alternative whose name begins with the earlier letter of the alphabet.”

Just as there is no morality to the Doctor’s precepts for selection, there is no morality for Jacob’s actions. His emotionally brutal seduction of Peggy Rankin, the English teacher he picks up on the beach, and his adultery with Rennie are equally without emotion or purpose. Traditional human motives, such as passion or even simple lust, are not truly applicable. Horner is acting only to be acting, to assert his existence. That the results are terribly destructive in terms of human life and suffering is, in the end, to him a matter of indifference, perhaps of incomprehension.

As counterpoint to Jacob’s frightening flexibility, Barth presents Joe’s mental and moral rigidity. In place of conventional morality he has erected his own system of rigorous intellectual honesty: Every action, every word, even every thought, must be capable of being explained and defended to the utmost. He is...