Hayek once wrote of Richard Cantillon: "In economics, just as in other sciences, it is by no means an exceptional occurrence to find that, no sooner has a "new" doctrine made its mark, than earlier, completely forgotten writers are discovered who perceived those newly accepted ideas with brilliant insight in their own day and set them down in their writings."
Unlearningecon points out that another example of this can be found in a recent post by Scott Sumner. Of course, the same can be said of Keynes. Keynes just does us the service of citing and even celebrating all the older thinkers that made similar points.
Unlearningecon also points out the supreme irony of all this: Scott Sumner is on record talking about how he doesn't think Keynes makes very much sense and doesn't care to read him. Hmmmm. Anyway, you all know by now what I think of the quality of Sumner's discussions of Keynes, Keynesianism, and Keynesians.