When Breath Becomes Air is the autobiography of Paul Kalanithi. It was first published in 2016. Paul Kalanithi was a neurological surgeon who was diagnosed with lung cancer. In this non-fiction book, Kalanithi writes about his life, including his childhood, his career, his cancer diagnosis, and finally his attempts to cope with this fatal disease.
The quote you are referring to shows how Kalanithi is trying to make sense of life through his work as a doctor. This statement shows that Kalanithi has finally understood that life is not just arbitrary and coincidental. He discovered that there is a greater picture in the background: “strands of biology, morality, life and death” all belong together and as a unit form the essence of what life is all about.
Within this unit, the role of a doctor is to do all that he can in order to save a patient’s life. The doctor is obligated to do so not just because he or she has the biological and scientific knowledge necessary. The doctor also has a moral obligation to help people continue their life and be with their loved ones. At the same time, doctors also have the power to decide over life and death. At times a doctor has “to allow the peace of death” if necessary. This great responsibility rests on the shoulders of every doctor, including Kalanithi himself. Therefore, as a doctor, Kalanithi feels that he plays an important part in this system and that this is very he belongs, both morally and professionally. It is his moral duty to help others in order to support and contribute to this almost “perfect moral system.”