This has been tremendously important in the development of our religious and spiritual evolution and remains an important aspect of cultural and artistic life around the world. The state of consciousness that gets achieved in getting high has been characterized as one where you first start by hallucinating lines and shapes, then you see a lattice network of shapes and images that form into a complex arrangement of pictures and then you go into the pictures and live in these different worlds. This is by no means a universal and textbook way it happens to everyone, but elements of this I certainly have experienced when smoking pot in the first year I smoked it and I also read a similar rant by Tom Wolfe on how Ken Kesey first came up with the character of 'Big Chief' in 'One flew over the cuckoos nest'.
I probably should have first started out with what I mean about getting high. Getting high is not drugs. Well, it's not just drugs. But on the subject, there are a lot of people who are plain down on drugs for a variety of good reasons, although narcotics have been extremely influential not only in religious experiences but in creating artistic pieces (see Alice in Wonderland, Sherlock Holmes or any music that ever came out of the late 60's early 70's).
What is meant by getting high is the process of getting yourself into an excited state (high heart rate, adrenaline release, heavy breathing, mild hallucinations) to a process of getting into an altered state (complete or major loss of connection to reality). This can be a use of drugs and of course a lot of cultures use this (YanoMamo in Brazil, Dyaks and Toraja in Indonesia) but it is only about one in 20-30. They include a variety of things from sweat lodges, doing impossible tasks, thinking about illogical questions or impossible problem solving, sex, pain infliction, intense physical activity, sleep deprivation, food and water deprivation, repetitive dance, chanting and drumming that matches the beat of the heart, isolation, etc.
Why this is important: it causes you to think differently. When I go into a sweat lodge I do not always hallucinate, in fact, I have yet to see the son of God. But I do, in the midst of a pounding heart, sweating skin, intense heat, see and think things that I have never experienced before. It is almost as if on the edges, you find new things.
One of the key ingredients according to an old professor (most of this stuff is from a course I took called 'the pre-history of religion') has been the element of boredom. When you get bored, your mind will start to wander to the point that it will eventually start thinking of things just to keep itself occupied. People who are kept in isolation for long periods of time will go mad. There brain goes to the edge. If you do it too long, it will never come back.
Getting high is a key to innovation. Innovation is a key to evolution. Get high.