Justin Weinberg at Daily Nous riffs off my post, Ideas Behind Their Time, to ask for philosophical examples. He nominates Gettier problems–i.e. counterexamples to the idea that knowledge is simply “justified true belief” as a possibility. The classic Gettier paper is from 1963. Wikipedia notes that the Indian philosopher Dharmottara has some clear examples c770 AD but as an element within the Western tradition the idea does seem behind its time.

I would nominate the following as philosophical ideas behind their time:

• Hume’s is/ought distinction: the idea that you cannot derive a normative conclusion from factual premises.
• Hume’s problem of induction: past regularities do not rationally guarantee future regularities.
• Rawls’s Veil of Ignorance: the principles of justice should be derived without knowing one’s own particularities of class, race, gender and so forth. Seems obvious as an idea.
• The Trolley Problem: similar ideas can be found earlier but the clean distinction between killing and let die or more generally omission and commission could have come much earlier. One might also think of the Prisoner’s Dilemma in this category of ideas or constructs that cleanly isolate an otherwise present but opaque idea.
• The analytic/synthetic truths distinction: some things are true by definition, others are empirical. Obvious and it can be found before say Kant, yet a clear earlier statement would have resolved many issues and seems well within say Aristotle’s capability.
• Aumann’s Agreement Theorem, technically, this requires Bayesian machinery and is difficult to formulate with precision, so I would not say the actual theorem was behind its time. But the underlying idea—that disagreement itself, not merely the arguments offered, should cause one to question and refine one’s own beliefs—could have been developed in Athens.
• I’d also nominate a package of ideas like abolitionism, equal rights for women, and religious toleration–each of these is tendentious as examples yet the basic package seems fairly obvious as a category and yet late. (Perhaps if the veil of ignorance had been thought of earlier so would these ideas!) Note, that I am not arguing that abolitionism or equal rights for women could have happened much earlier only that these ideas were behind their time–the ideas were morally obvious even if not institutionally feasible.

Note also that I am not arguing that these ideas are all correct, only that they were philosophical ideas behind their time. More examples?