She believed in nothing. Only her scepticism kept her from being an atheist.

The line is a pointed paradox: the subject’s disbelief is so thorough that even the label “atheist” (which still presupposes a definite stance toward God) feels too committed. Sartre often distinguishes between lived attitudes and ready-made identities; here, “scepticism” functions as a refusal to settle into any doctrinal position, including the negative doctrine of atheism. The remark also satirizes a certain intellectual posture—treating doubt as a protective shell against the responsibilities that come with affirming or denying ultimate meanings. In existentialist terms, it suggests a flight from commitment: scepticism becomes a way to avoid choosing, and thus to avoid owning one’s freedom and its consequences.