This essay introduces the terms “nomothetic” and “idiographic” to characterize the current debate about whether the field of family therapy should accumulate and apply knowledge about patterns of adjustment that hold across different families, or whether the field should consider each family as utterly unique, and should tailor interventions solely on the basis of these unique qualities. Embedded in this debate are the arguments for and against quantitative research, disagreements about the value of clinical prediction and interobserver reliability, as well as the issue of whether therapists can rightfully claim to possess “expert knowledge.” The essay begins with the personal‐professional anecdote that stimulated me to explore this debate in greater depth. It continues with a brief discussion of the historical context of this debate, particularly noting the parallels between the methodological issues in personality research and those facing family therapy. The nomothetic‐idiographic debate in family therapy theory, research, and practice is then described. The essay ends with the suggestion that family therapy view nomothetic and idiographic thinking as complementary, and that the field strive to develop an integrated, “idiothetic” approach to family therapy re