Financial Regulation via Chronophone
A few years ago, Eliezer Yudkowsky speculated about the effects of a chronophone:
If we sent advice to increase financial regulation to politicians of a mere decade ago via this chronophone, what would it come out as? If we said “Make sure financial institutions only invest in the soundest securities,” it might come out as “Only invest in top-rated mortgage securities and European sovereign debt.” After all, the major worries of most of the naughties were that foreigners would compete with Americans and that a combination of wars and tax cuts would drive America bankrupt. (Clearly, we should only invest in industries that were immune to imports and off-shoring and only invest in sovereign debt from peaceful countries unafraid of taxes.)
Archimedes of Syracuse was the greatest mathematician and engineer of the ancient world. Imagine that Archimedes invented a temporal telephone ("chronophone" for short) which lets him talk to you, here in the 21st century. You can make suggestions! For purposes of the thought experiment, ignore the morality of altering history - just assume that it is proper to optimize post-Archimedean history as though it were simply the ordinary future. If so, it would seem that you are in a position to accomplish a great deal of good.
Unfortunately, Archimedes's chronophone comes with certain restrictions upon its use: It cannot transmit information that is, in a certain sense, "too anachronistic".
You cannot suggest, for example, that women should have the vote. Maybe you could persuade Archimedes of Syracuse of the issue, and maybe not; but it is a moot point, the chronophone will not transmit the advice. Or rather, it will transmit the advice, but it will come out as: "Install a tyrant of great personal virtue, such as Hiero II, under whose rule Syracuse experienced fifty years of peace and prosperity." That's how the chronophone avoids transmitting overly anachronistic information - it transmits cognitive strategies rather than words. If you follow the policy of "Check my brain's memory to see what my contemporary culture recommends as a wise form of political organization", what comes out of the chronophone is the result of Archimedes following the same policy of looking up in his brain what his era lauds as a wise form of political organization.