Last trip I was thinking about the Doors of Perception, specifically Huxley's idea that the brain and ego act as a filter to reality, purely as a survival mechanism, and that drugs like LSD, mescaline, etc, remove this filter and allow us to experience our surroundings as they truly are. This suddenly made so much sense to me, in a much bigger way than any of the other thoughts and epiphanies I've had on acid, which often 'made sense' at the time but later were easily dismissed.
Like, it's undeniable that acid heightens your senses - your vision seems crisper, and colours richer, and you can much more clearly hear the details of music. Touch, taste and smell are all also amplified to a big extent fairly often for me. So, to me, it seems obvious that your body is capable of utilising its sensory inputs in a much more powerful way than that experienced in day-to-day life. But for your senses to be constantly in top gear would be much too overwhelming (hence why a filter for such is a survival mechanism).
Also, the fact that LSD acts as an antagonist (it is a serotonin antagonist, right?) in your brain, whereas non-psychedelic drugs tend to be agonists (including weed I believe) ties in with this idea as well. As an antagonist, rather than causing additional neurological processes to occur (eg MDMA releases serotonin) LSD inhibits them, and I think that this inhibition could be the 'removal' of the brain's filter.
Basically I am led to believe that Huxley was definitely onto something, and that psychedelics are completely unlike all other drugs. What do you guys reckon?