Matthew Yglesias explains, to the Pithlord's satisfaction, why meaning isn't about the private intention of the speaker/author. Somebody in the comments thread points out that private meaning might be important in certain kinds of speech/writing. But it is beyond dispute that legal documents are not that kind of utterance.
This was all inspired by Stanley Fish's embrace of the "What would Madison do?" kind of originalism, which everybody in the legal world considered dead. In Canada, it is paradoxically even more silly than in the US with its long-dead framers, since the drafter of the Charter, Barry Strayer, is an intermediary appeal judge on the Federal Court. If the WWMD types were right, he would decide all his cases by trying to reminisce about what he would have done back when he was a wet-behind-the-ears DOJ hack, and once he introspected this, then his panel colleagues and the SCC would just have to do what he said.
If Constitutional adjudication were about meaning, then this would all be very important. But, at least most of the time, constitutional adjudication is *not* about the meaning of terms like "equality" or "liberty", but their application. Is a ban on Sunday shopping contrary to freedom of religion? You don't find out by asking English speakers what "freedom" and "religion" and "of" mean; you find out by inquiring as to the secular purposes of such legislation, its effect on religious minorities and so on.
The Pithlord is very sympathetic to the concern behind originalism. He worries about judicialization of decisions that ought to be decided democratically. But originalism isn't going to do anything about this concern. If it is of the WWMD type, it is absurd, and would require the kind of communing with the dead that has wisely not been part of the Canadian public policy process since King. If originalism is recast in more plausible form, then it doesn't actually do anything useful, at least not in the cases that people worry about.