The detection of "questions that are no longer asked" is difficult. Old questions, like MacArthur's old soldiers, just fade away. Scientists and scholars in hot pursuit of new questions neither note nor mourn their passing. I regularly face a modest form of the disappearing question challenge when a textbook used in one of my classes is revised. Deletions are hard to find; they leave no voids and are more stealthy than black holes, not even affecting their surrounds. New text content stands out, while missing material must be established through careful line-by-line reading. Whether in textbooks or in life, we don't think much about what is no longer relevant.
My response to the inquiry about questions that are no longer asked is to reframe it and suggest instead a common class of missing questions, those associated with obsolete and inappropriate metaphors. Metaphor is a powerful cognitive tool, which, like all models, clarifies thinking when appropriate, but constrains it when inappropriate. Science is full of them. My professional specialties of neuroscience and biopsychology has mind/brain metaphors ranging from Locke's ancient blank slate (tabula rasa), to the more technologically advanced switchboard, and the metaphor de jour, the computer. None do justice to the brain as a soggy lump of wetware, but linger as cognitive/linguistic models. Natural selection in the realm of metaphors is slow and imperfect. Witness the reference to DNA as a "blueprint" for an organism, when Dawkins' "recipe" metaphor more accurately reflects DNA's incoding of instructions for organismic assembly.
ROBERT R. PROVINE is Professor of Psychology and Neuroscience at the University of Maryland, Baltimore County, and author of Laughter: A Scientific Investigation.