This seems line of thinking seems to equivocate enlightenment with flipping a switch in your brain.
It is. Enlightenment - like anything - can only be achieved in the infinitesimal moment. Once the change in perception has occurred, that gate is opened, and one can progress further down the path. (Also, there are many traditions within which enlightenment is a succession of realisations, not merely a single one).
I engage in daily spiritual practice (not "once" or "twice" a day; almost all the time I'm living, actually). The increments are not imperceptible; one of the most gratifying things I find about spiritual experience is that it becomes noticeably more tangible as one goes deeper.
These civilizations were great because of strong leaders and strong value systems, and outside of the Hindus neither of those attributes can said to have been significantly influenced by drugs, at least insofar as the Greeks, Romans, Japanese, and Chinese are concerned(None of the major schools of Greek philosophy encouraged drug use, nor did most sects of Buddhism). The shamans and soothsayers of old probably did more harm than good with due to their promulgation of silly superstitions alongside actual Truth. Drug use--for the sake of spirituality or any other reason--is discouraged by most religions, and for good reason: it is an anachronism that should be left for primitive jungle peoples.
Their leaders were initiated into the mysteries of their religions (which almost universally means taking psychedelics). Plato, Pythagoras, Parmenides, Heraclitus, Zeno: these Greek philosophers (and many more - in fact, almost all Greeks for two thousand years) took the Kykeon, and firmly advocated its use. The shamans are correct in their assessment of the spirit worlds to which we have access; theirs is not "superstition" but unclouded experience of what is, presented in metaphor (just as it is for all other people). The use of intoxicants is discouraged by religions (for good reason); the use of entheogens is, more often than not, supported by all but the most established monotheisms.
THC 'dis-orchestrates' the brain and causes schizophrenia-like symptoms.
Interesting, given that I have never, nor do I know anyone who has ever had responses to cannabis mirroring "schizophrenia-like symptoms" (I suppose they mean temporary psychosis? I put most of that kind of stuff down to spiritual reasons, nowadays, having investigated these substances enough).
Furthermore, most of the cannabis users I know (including my -former- self) are lethargic, unmotivated, and live unhealthy lifestyles. Note that I am not accusing you of any of these things. There's always a duck-billed platypus to mess up the nice and neat rules people come up with.
This I will most certainly grant: most potheads are losers. When weed becomes your life, and you're only exit from your home is to work, get food, and pick up, something has gone drastically wrong.
I have experimented with nootropics such as piracetam and aniracetam, and while they did provide a high kinda sorta like marijuana, what with enhanced perception of colors and more abstract thinking but minus any euphoria or body high, in the end all they did was make me psychotic. Not smarter. I did a lot of research on those drugs, and not once did I encounter a reliable source for the claim that such drugs increased IQ.
There is a paucity of research on the effects of drugs on IQ. But seeing as it is mostly genetic, and that the part that is experiential is done developing by the end of childhood, common sense informs me that drugs cannot raise IQ. I wouldn't be surprised if they lowered IQ, though.
There is at least one mechanism for the raising of IQ which is enhanced through the ingestion of a drug. For example: taking speed to help you get through a 24 hour arithmetic challenge, you will most likely have increased in your ability to recognise and map patterns at the end of that experience (and a horrible comedown!). Still doesn't mean taking speed is a good idea, though.
However, don't kid yourself: IQ is important and will determine your lot in life; wisdom is not the be-all end-all. I want to be a computer programmer. In order to be a programmer, one has to have above average intelligence. I am sure you have similarly aspire to take up a profession which requires a baseline level of intelligence.
I can assure you, one does not have to be of above average intelligence to be paid
as a programmer (I've known too many idiots in that area), though it is certainly recommendable if you want to be able to do good work!
I honestly believe, now, that what we call the "rational faculty" is almost entirely useless for anything other than understanding cause and effect. The reason IQ is important nowadays is because we've made it important. However, Man can live in conditions and cultures in which such an affinity for reduction is not prized; instead, the intuition is raised above all else, or the mind's faculties are held in balance, or some other variant, etc.
Drugs are not indicative of an adventurous spirit...
But see? Insulting someone else's lifestyle just because it differs from your own only makes for more venom and vitriol. I am not preaching, I am probing.
I don't particularly aim my previous statement towards any one person, but it is an attitude which I see cropping up here (not just in this thread, I might add). Is it not my duty to point it out, if I feel that my comrades might be slipping up? Though, of course, I recognise that exactly the same argument might be levied against me, from the other perspective ; ) Don't worry that I might have been insulted by any of this! Offense is taken, not given.
Were drugs really necessary to arrive at those conclusions?
I'll go through my 'revelations':
-- The complimentary nature of the sexes. I remember thinking this on my first acid trip. All it takes is interaction with the opposite sex to realize this.
-- The importance of family. Again, common sense stuff that just takes a little bit of self-reflection.
-- A good day is a productive day. I'll admit, smoking weed made me realize I was wasting too much time playing videogames. Probably would've realized this anyway once I got into physical fitness.
-- Telepathy. This is the only revelation I probably never would have had without drugs. Not too terribly important, though.
-- The importance of never giving up. A cliche, but seemed profound at the time. Experienced this thought as a fractal, as though every thought I had during the trip was a permutation of this idea. Really a no brainer.
-- The existence of other minds radically different from my own (but at the same time, identical). I remember blacking out for a second while thinking this on acid, not sure why. Again, common sense stuff you teach yourself as you learn and grow.
With the exception of telepathy, none of these things truly required drugs to realize. I admit drugs have an interesting way of 'crystallizing' thoughts, but they really just get you to think about and appreciate the obvious, something that can be achieved by mindfulness alone.
I have to say, I knew most of those before I took any drugs, and many of the drugs have shown me again the importance of such things. It's all well and good to say "this is so: remember it", but it can be helpful to have a reminder every once in a while.
I perhaps should have made more of a point about the spiritual insights: for me, the workings of the subtle bodies are made apparent through the appropriate use of cannabis. When used for meditation, one's awareness of the body is almost forced to extend to that which one cannot usually feel. There are devices, mechanisms, and pathways within our own bodies which can be shown through nothing other than self-exploration; these are made instantly apparent through hallucinogens.
"Telepathy" (or, more accurately, the transference of emotion between two people) is something which I discovered without drugs, actually, though I find that some drugs massively improve one's ability in that area (2CB, mushrooms, and cannabis are great for it). Still, it's perfectly possible without such things, and sometimes even easier after a while. Smoking lots of weed is like wearing training weights, beyond a certain level: the world is made murkier, less clear; can you still function as well as you normally would? (Answer: yes, by now.)
Thanks for the interesting post!