Fun fact: the expression “if all you have is a hammer, everything looks like a nail” can be attributed to Abraham Maslow. Yes, the psychologist, he of the famous hierarchy of needs. One of the first recorded instances of this metaphor is in Maslow’s 1966 book, The Psychology of Science: A Reconnaissance. Here is the original context:
When my work in psychopathology led me to explore nonpathology—psychologically healthy people—difficulties came up that I had never had to face before. Health is itself a normative word. (…)
The study of these relatively healthy people and their characteristics opened up dozens of new problems for me personally and as a scientist, and it made me dissatisfied with dozens of old solutions and methods and concepts that I had taken for granted. These people raised new questions about the nature of normality, of health, of goodness, of creativeness and love, of higher needs, beauty, curiosity, fulfillment, of heroes and the godlike in human beings, of altruism and co-operativeness, of love for the young, protection of the weak, compassion and unselfishness and humanitarianism, of greatness, of transcendent experiences, of higher values. (…)
These “higher” psychological processes in the human being did not fit gracefully and comfortably into the extant machinery for achieving reliable knowledge. This machine, it turned out, was much like something I have in my kitchen called a “disposall,” which nevertheless does not really dispose of all things but only some things. Or to make another comparison. I remember seeing an elaborate and complicated automatic washing machine for automobiles that did a beautiful job of washing them. But it could do only that, and everything else that got into its clutches was treated as if it were an automobile to be washed. I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail.
In a word, I had either to give up my questions or else invent new ways of answering them. I preferred the latter course.
I guess I can see why “if all you have is an elaborate and complicated automatic washing machine for automobiles…” didn’t stick around.