This month I would like to take a break from my lecture style of column-writing to pose a question to readers. Seriously, I don't have an answer to this, so I'd like your opinion: Does fundamental social change generally come from the top down or the bottom up?

By top down, I mean that governments and legal systems effect social change by legislating and rule-making. In other words, if leaders want to stop people doing something they consider unsavory, they make it illegal. This may occur with or without popular support, but the prototypical example would be legislating away a bad social habit (say, lax speed limits or unstandardized legal drinking ages) regardless of clear public approval.

By bottom up, I mean that social change arises from a critical mass of people putting pressure on their elected officials (and each other) to desist in something socially undesirable. Eventually this also results in new rules and legislation, but the impetus and momentum for change is at the grass-roots level, thanks to clear public support.