What is a liberal?

Noticing on Facebook that a number of my friends classify themselves as politically liberal, I tried to look up what this is supposed to mean.

My 1983 Chambers Dictionary offers only vague generalities: “befitting a freeman or a gentleman, directed towards the cultivation of the mind for its own sake, disinterested, generous, noble-minded, broad-minded, ...”

The Oxford English Dictionary says, “Favourable to constitutional changes and legal or administrative reforms tending in the direction of freedom or democracy.”

Wikipedia describes liberalism as “the belief in the importance of individual freedom.”

The American Heritage Dictionary is the most specific, giving two politically relevant definitions:

• “A political theory founded on the natural goodness of humans and the autonomy of the individual and favoring civil and political liberties, government by law with the consent of the governed, and protection from arbitrary authority.”
• “An economic theory in favor of laissez-faire, the free market, and the gold standard.”

Taking all this into consideration, it seems to me that a lot of people these days could describe themselves as liberal in at least some senses, including me. I have doubts mainly about the natural goodness of humans and the gold standard; but in other respects I'm probably more liberal than most of the people who describe themselves as such.