Ism is also Douglas Hofstadter's -ism for describing Zen Buddhism as a spirituality, and, when applied to the art world, something akin to transcendentalism. It was coined in the timeless Gödel, Escher, Bach: An Eternal Golden Braid.
Ism is interesting as an -ism because it lacks a prefix, leaving only the suffix to awkwardly jut outwards. The lack of any idea in front of the -ism reflects the lack of any ideas or distinction in Zen. Even the name is evocative of the ideas and practices of Zen: it first seems to be out of place, because it's missing something, but in actuality, it is your preconceptions that throw you off, and when you are at peace with the universe in the stage of enlightenment, it's all cool.
Or, at least, that's what I gather. I have not yet attained enlightenment, so don't quote me on this.
The actual passage in GEB is below.
Ism, The Un-Mode, and Unmon
If words are bad, and thinking is bad, what is good? Of course, to ask this is already horribly dualistic, but we are making no pretense of being faithful to Zen in discussing Zen—so we can try to answer the question seriously. I have a name for what Zen strives for: ism [emphasis in original]. Ism is an antiphilosophy, a way of being without thinking. The masters of ism are rocks, trees, clams; but it is the fate of higher animal species to have to strive for ism, without ever being able to attain it fully. Still, one is occasionally granted glimpses of ism. Perhaps the following kōan offers such a glimpse:7
Hyakujō wished to send a monk to open a new monastery. He told his pupils that whoever answered a question most ably would be appointed. Placing a water vase on the ground, he asked: "Who can say what this is without calling its name?"
The chief monk said: "No one can call it a wodden shoe."
Isan, the cooking monk, tipped over the vase with his foot and went out.
Hyakujō smiled and said: "The chief monk loses." And Isan became the master of the new monastery.
To suppress perception, to suppress logical, verbal, dualistic thinking—this is the essence of Zen, the essence of ism. This is the Un-Mode—not Intelligent, not Mechanical, just "Un". Jōshū was in the Un-mode, and that is why his 'MU' unasks the question. The Un-mode came naturally to Zen Master Unmon:8
One day Unmon said to his disciples, "This staff of mine has transformed itself into a dragon and has swallowed up the universe! Oh, where are the rivers and mountains and the great earth?"
Zen is holism, carried to its logical extreme. If holism claims that things can only be understood as wholes, not as the sums of their parts, Zen goes one further, in maintaining that the world cannot be broken into parts at all. To divide the world into parts is to be deluded, and to miss enlightenment.
A master was asked the question, "What is the way?" by a curious monk.
"It is right before your eyes," said the master.
"Why do I not see it for myself?"
"Because you are thinking of yourself."
"What about you: do you see it?"
"So long as you see double, saying 'I don't', and 'you do', and so on, your eyes are clouded," said the master.
"When there is neither 'I' nor 'You', can one see it?"
"When there is neither 'I' nor 'You', who is the one that wants to see it?"9
Apparently the master wants to get across the idea that an enlightened state is one where the borderlines between the self and the rest of the universe are dissolved. This would truly be the end of dualism, for as he says, there is no system left which has any desire for perception. But what is that state, if not death? How can a live human being dissolve the borderlines between himself and the outside world?
In summary, Hofstadter is trying to communicate what the underlying philosophy of Zen is, and how futile it is to try to approach it from all conventional ways of viewing the world. If the point of true Zen is entire, full oneness, how can we differentiate anything enough to discuss how to attain it? For the change from our dualistic worldview to a such a holistic one is definitely a change; and when there is only one, how can you describe change? And, if we do take the idea of discussing Zen outside of Zen—the theme of making distinct the act of working within a system and working outside-of-yet-about a system is one of many in GEB—then can we even truly capture the idea of oneness from within the constraints of dualism?
The mentioned footnotes:
7 Paul Reps, Zen Flesh, Zen Bones, p. 121.
8 Gyomay M. Kubose, Zen Koans, p. 35.
9 Zen Buddhism (Mount Vernon, N.Y.: Peter Pauper Press, 1959), p. 22.
For the record, GEB has plenty more to say on the topic of Zen, as well as many other things. It's well worth the read.