Septimus Warren Smith is the other side of the coin in this study of sanity and insanity. Septimus went to war, he tried to defend his country, and he attempted to become a "man." He lost. Clarissa did not do battle; she withdrew and married a safe man who would not dare her to be more of a woman than she believed herself capable of being. And she lost. She believed that marriage would destroy both herself and Peter. She considered consequences; Septimus did not.
When the novel begins, both Clarissa and Septimus are out and about in London. Both absorb the exquisite beauty, but Clarissa does not weep at what she sees and hears and feels. She does not release and exude her excitement. Her reactions and Septimus' are similar but Septimus' are far more intense.
Both Septimus and Clarissa feel that they are outside, looking on, and at the same time dashing headlong through life. They are both alternately very happy, then very worried and fearful. Virginia Woolf shows us the moment of terror in Septimus' heart and then relates it to what supremely matters to Clarissa. To her, what supremely matters is what one "feels" — and what terrifies Septimus is that he cannot "feel." Yet despite their similarities, Clarissa and Septimus do differ. Septimus is concerned that he cannot feel and care for another person; he is horrified that he is unable to feel as, say, Peter Walsh might feel. Clarissa is afraid of "feeling too completely." Clarissa is a bit guilty of Sir William Bradshaw's sin — of giving service to Proportion. But, one might ask, what is one to do if he, like Clarissa, is convinced that he is not capable of flinging himself at life — and surviving? Should he make himself a willing victim? Clarissa is unlike Peter and Sally and Septimus; she does not have their abandon nor their flair for rebellion.
The quality most central to Clarissa and Septimus is their insistence on no one's having power over them. Septimus refuses to let Bradshaw use him for experimentation and Clarissa is equally as defiant of Miss Kilman's determination to dominate her. But Clarissa has also refused Richard's, and Peter's, intimacy because of her intense fear of domination. In this novel Virginia Woolf includes flaws and impurities in her major characters so that human nature, and not metaphors, are revealed.