"Question 6. What Picks the Correct Vacuum? This is one of the great mysteries of the theory which appears, at least when treated perturbatively, to possess an enormous number of acceptable (stable) vacuum states. Why, for example, don't we live in ten dimensions? Does the theory possess a unique vacuum, in which case all dimensionless physical parameters would be calculable or is the vacuum truly degenerate, in which case we would have free parameters? ..."