Consciousness is often said to disappear in deep, dreamless sleep. We argue that this assumption is oversimplified. Unless dreamless sleep is defined as unconscious from the outset there are good empirical and theoretical reasons for saying that a range of different types of sleep experience, some of which are distinct from dreaming, can occur in all stages of sleep.
If the threshold changed, the actual definition changed. The same words to describe a different point. If the definition described two different things, its changed. That's basic and simple reasoning. If a definition no longer describes the same thing, it's because it's actual meaning has changed.
