Originally Posted by MSD

A sound engineer posing as a scientist engages in quack science. This man has confused the many worlds interpretation with dimensional physics. Alternate and parallel universes may be theorized by some, but should not be confused with higher dimensions. Above the fourth, dimensions exist in sizes only dealt with in quantum physics; this video displays a fairly strong grasp up to that point as the fourth (time) dimension in euclidean space represents the length of a vector. The only reason to posit these dimensions as such is to push string theory, which is non-falsifiable and therefore as invalid as competing non-falsifiable theories.

In short, this has nothing to do with science and everything to do with selling books on a subject in which the author has no business claiming to be an authority.