A different view is Huxley's reducing valve theory of consciousness. On that view we are bombarded by an overwhelming amount of sensation and information every

A different view is Huxley's reducing valve theory of consciousness. On that view we are bombarded by an overwhelming amount of sensation and information every second -- so much that if we were aware of it all we wouldn't be able to function. So the brain functions like a valve and reduces this flow of sensation and information to a manageable level -- just enough so that we can do practical things such as go to work , do the dishes, etc.. Psychedelics have the effect of opening up this valve so that one experiences more of what one is sensing, so one actually sees more of reality than one does in one's ordinary waking state of consciousness. The problem is that it's harder to function in such a psychedelically open state (at least with large doses of psychedelics, like the kind Huxley was using back in the 60's). Under the influence of mescaline, for example, Huxley found the dishes in the sink too beautiful to wash. This is just one alternate view of how psychedelics work. There are many others.