What is Reason?

Last night Supreme Court Justice Stephen Breyer spoke at the John Hopkins School for Advanced International Studies on the need for American judges to understand international laws. Referring to being in India on 9/11, he reflected that the division in the world is not between nations but between those who accept reason and those who don't. But what is reason? Use of technology and deductive logic might be included but the terrorists used them to good effect, deducing that airliners could be used as missiles and learning how to fly them. It seems that Justice Breyer meant something else, perhaps resolving differences through negotiation or mediation within an legal framework rather than through violence. Or, of course, through a judicial system. Such a meaning would also require that parties accept the result as legitimate even when they don't reach their goals. So perhaps reason, to him, means acceptance of the rule of law and an associated legal structure. Not "unreasonable." But what if laws are not the same everywhere? What if sharia is the accepted framework? Is his distinction a tautology?