Gurdjieff once said:
The Enneagram is an experience of that little; but to understand it we need much experience. It can become for each of us an endless source of understanding and inspiration, for it enables our thought processes to shape themselves both according to the shape of the world and to that of our own being. It is an instrument that enables us to see when and how events conform to cosmic laws and so recognize what is possible and what is impossible in human undertakings.
The Enneagram is an instrument to help us to achieve triadic perception and mentation. Whereas our ordinary mental processes are linear and sequential, the world in which we live is threefold. According to Gurdjieff, threefoldness is one of the "fundamental Sacred Cosmic Laws" and must be studied by anyone who wishes to understand himself and the world in which he lives.
We find it hard to look at the whole of what is happening in and around us because our thinking is linear, by which I mean thinking along one single line or by association. We miss significant episodes and cannot understand how it is that processes go the way they do.
When things go wrong we seldom know where, nor how to put them right. This is not a serious handicap in thinking about processes that are themselves linear, such as most of those in the material world. However it breaks down when we try to think about man and his ways, for these are not linear.
Man is very complex and his life is always made up of different processes that cannot be separated without falsification. To think about man effectively we must get beyond linear thinking in order to see the inner cohesion.
The spiritual world is totally non-linear and this is why we cannot ordinarily think about it at all. We must therefore find a new way of thinking.
In order to change our way of thinking we have first of all to recognize that it is not a matter of looking along several different lines at once but recognizing that there is structure in what we are looking at. The structure may be imperfect, but if it were not there at all, we could understand nothing.