From Martin Arrowsmith's beginnings at medical school, Martin is against the philosophy and practice of the physician. He is a man who admires more the science of Gottlieb than that of Dean Silva, the compassionate caretaker. He believes that the search of the laboratory scientist is purer and more "true." He often looks down on the "country doctor" in arrogance, even. His ideal is to gain the cold sureness of Gottlieb and yet, Martin is constantly shifting. At one point, Martin finds Silva admirable and he becomes a physician in Wheatsylvania and yet he does this more out of force than will.

Moreover, once he becomes a physician, the respect of the townspeople for him is in constant flux, for different reasons. Martin often looks down on his patients and, further, is not contended with the responsibilities of the country doctor - he needs more. His curiosity forces his visions to extend beyond that of the local success of the country doctor and even passed the notoriety of the big city surgeon (like Angus Duer). Further, Martin is not altogether social or good with people and, while in medical school, he cannot develop a "bedside manner."

From the beginning Gottlieb had told him that he would not make a good doctor, though he may make for an excellent laboratory scientist. Further, and most importantly, Martin does not make a good physician because he is not happy in the practice of it. For, Martin is not inept and, in fact, is quite capable of saving lives. Further, he is often compassionate, despite himself. And still, he is miserable when he is not in the laboratory and therefore does not put his whole self into the practice of the physician as he does when he is in the lab.

Max Gottlieb is Martin's ideal and true mentor. Gottlieb's presences, even when he is not physically there, is present throughout the novel because Martin is constantly calling upon him in memory. In fact, Martin calls him forth as one would almost call forth a god in prayer. He calls him to mind when he is in trouble, when he fears falling into temptation, and when he most needs a reassuring hand. Gottlieb is a man who, most of the time, is true to his "religion" of science and Martin longs to be like him, from the moment he hears about him at one of Edward Edward's "At Homes."

This is not to say that his relationship with Gottlieb is altogether idyllic. They fight and part ways many times, just as Martin and Leora fight. Also, Martin will not be able to fully lead his own life until he is free of Gottlieb. Because Martin is always trying to please him, he feels a kind of release (the lifting of a burden) when Gottlieb resigns from the institutes because of senility. Although Gottlieb's senility hits Martin at heart, it is something that is necessary for Martin's growth—in short, he must outgrow the space between the wings of his father in order to truly be happy in the world at large.

The end of the novel is optimistic in the way that the beginning of the novel is. At the beginning the reader glimpses at the life of Martin Arrowsmith's pioneer great-grandmother. His fourteen-year-old great-grandmother has lost her mother and has her sick father riding in the back of her wagon, and yet she looks forward to the west and is ready to see the world. When her father asks her to stop, she says: "We're going on jus' along as we can. Going West! They's a whole lot of new things I aim to be seeing!" This spirit is precisely that of Martin at the end of the novel.

Martin has decided to abandon the "comfort" of the Institute for the freedom of independent work. He has retreated into the woods and looks forward to the future. He knows failure may be ahead, but he is prepared for it so that although the novel ends in the world "fail," it is a failure Martin is willing to accept and one from which to venture forth. It may be that this is simply another one of Martin's "good moments," but, since the novel ends with the idea of failure, we cannot help but feel pessimistic. Also, it cannot be said that Martin has not learned from his experiences, even though, at times, it seemed he would never be able to do so. Further, it is tragedy that allows him this freedom. Martin, by the end, finally finds his place. He admits to being an outsider, a "barbarian," as Leora had phrased it and yet, not without losing his loved ones first.

Martin loses Leora and Gottlieb, and yet Martin cannot be alone. It may be different this time around, but that is not to say Martin may not fall into another relationship that holds him back. Therefore, the ending depends on whether you believe Martin has attained his freedom for good, or whether this journey into the woods is just a phase in his long life.