Good. I completely disagree with Peter’s opinions about string theory, and think that his accusations that the Landscape is non-scientific are completely off the mark. But his objections are not crazy, and his dislike for the theory is grounded in an informed scientific judgement. (Sometimes more than others, but that’s a matter of personal opinion.)
The whole discussion is a nice contrast with the Intelligent Design mess. The fact is, we don’t know what is the correct theory that unifies particle physics with gravitation. String theory is far and away the leading candidate, but its status as leader is a reflection of the educated judgement of the experts, not any airtight evidence. This judgement comes from looking at various pieces of information — what we know about gravitation, and quantum mechanics, and particle physics, and the history of ideas in physics, and the mathematical structures underlying gauge theory and general relativity, as well as an intuitive feeling for what principles are most important and what clues most worth pursuing — and deciding which path toward progress is likely to be fruitful. When people like Peter (or Lee Smolin) read these tea leaves, they come to a different conclusion than most scientists in the field. But it’s healthy disagreement among professionals working at the edge of what we know and don’t know — not politically-motivated intervention from people who have no clue, just an agenda, and operate completely apart from the scientific mainstream. To people looking in from the outside, I hope an accurate picture comes across: there is a widespread feeling that string theory is the best hope for a quantum theory of gravity, but it’s not a settled issue, and we’re working in good faith on moving forward.
So I’m happy to see this side of the argument represented in the popular press, even if I disagree — we shouldn’t be afraid of the free market of ideas. If people don’t agree, they should explain the sources of their disagreement rationally. There is always the danger of misprepresentation of course, and in this case there is an obvious worry — that a spate of stories will appear about how string theory is in trouble, and a house built on sand, and so forth. That might be true, but certainly isn’t the impression I have from talking to string theorists. In any event, I hope that we defenders of the theory can stick to the high road, and welcome this intervention in the discussion of these important ideas.