Do you know if there has been a serious scientific study of this technique? Otherwise, you're being a bit disingenuous in subtly applying the "unscientific" label. The set of things that are true is much larger than the set of true things that have been proven scientifically.
So I should have formulated myself more carefully by saying: Studies indicate that short periods of sleep is less effective than long ones, and that each individual requires a certain amount of sleep per night (but which varies with individual and then as you age).
He did go so far as to say something about how he thought methods advocating that you can train yourself to sleep less are "dangerous", given how much sleep deprivation affects your health and ability to do things like drive or operate other machinery safely.