The idea that many different laws of physics are possible has been the subject of speculation for years, but a firmer foundation has emerged recently from string theory, the “theory of everything” in physics. As a leading string theorist, Leonard Susskind is well placed to explain these developments. In 2003 (see http://arxiv.org/abs/hep-th/0302219), he coined the term landscape to summarize two related ideas. The first is that the mathematical edifice of string theory predicts many possible consistent laws of physics, not only the ones that we happen to observe. Furthermore, it is possible within modern inflationary cosmology to have a “multiverse” where all these possibilities actually exist in different regions. Not all string theorists accept this conclusion; if true, it represents the crushing of their dream that string theory would ultimately explain why nature has had to function in the way that it does.
Because the landscape idea has broad implications, it is good to see that in his new book, The Cosmic Landscape, Susskind has cast the arguments into a form suitable for a general readership. It is clear, though, that Susskind is not just intent on educating readers—he wants to pick a fight.
more from American Scientist here.