I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail.

Abraham H. Maslow, best known for his work in humanistic psychology and the “hierarchy of needs,” used this remark in the early 1960s while criticizing narrow, single-method approaches in psychology and the social sciences. In that period Maslow argued that researchers and practitioners often become overcommitted to one favored technique—whether a test, a statistical method, or a therapeutic framework—and then force complex human problems to fit that tool. The line functions as a caution against methodological monism and professional tunnel vision, reflecting Maslow’s broader push for a more pluralistic, holistic understanding of human motivation and behavior.

The quote warns that our instruments shape our perception: when we rely on one dominant tool, we begin to see every situation as requiring the same kind of intervention. Maslow’s “hammer” stands for any habitual method, theory, or skill; the “nail” is the world reduced to problems that tool can address. The insight is both epistemic and ethical: it critiques how expertise can become a bias, encouraging oversimplification and inappropriate solutions. In Maslow’s humanistic frame, it urges flexibility—choosing methods that fit the person and context rather than forcing people to fit a method.

1) “If the only tool you have is a hammer, you tend to see every problem as a nail.”
2) “To a man with a hammer, everything looks like a nail.”
3) “When all you have is a hammer, everything begins to look like a nail.”