[The Beach Boys] are moving forward all the time.

Each Beach Boys album since Pet Sounds has been (or seemed) a little less sophisticated. Retrogression? Not at all, but to prove that, we'd better decide what "forward" is.

Forward is the direction in which time moves. It's kind of like "out," which is the direction in which cosmic matter moves. There is no possibility of reversal inherent in this movement, nor even of angular shift. Those concepts have no meaning. Can a line stretching from zero towards infinity turn around? I mean, try to visualize it. At best, it would no longer be a line; and the basic assumption we make in calling something a line is that it is, at least, a line. So forward is a description of how time moves, just as outward might describe how space moves, if we think of "space" the concept...