The kind of recycling MMM generally talks about--re-using construction materials and such that would have been trashed otherwise--is almost unquestionably good for the environment, since it requires less stuff to be cleaned, processed, prepared, packaged, shipped, and sold. Likewise, I don't think anyone could argue that it's a bad thing to repurpose various things that might be thrown away in lieu of buying new stuff.
But what about typical recycling, as in the recycling of paper and plastic products? Is it good for the environment, or is it just a feel-good ritual?
To answer this question, I think a lot of us will have to drop our "common sense" because we have essentially been raised to recycle and the assumption that it's good for the environment is rarely ever substantiated, let alone challenged.
Here are, as far as I can see, the parameters. If recycling is good for the environment, it must:
Reduce the amount of raw resources being used
Reduce pollution
Create safe products
Be cost effective in terms of labor and materials used in the recycling process
I am not sure I've arrived at my answer yet, but after checking a few wikipedia pages, reading a few articles, and watching Penn and Teller's episode on the issue, I am pretty skeptical about--at least--recycling plastics. Most plastic sent to recycling plants seems to be just thrown away. And the recycling industry, naturally, wants people to keep recycling so that it stays in business, and recycling is such a part of our culture that few people seem to really question it.
I have to do more research, but as of now, I can safely say that we should use less stuff--a LOT less stuff--and repurpose what we already have before thinking about disposing of it.