Most engineering, most science, most art, and most problem-solving, involves operations of the mind that we are rarely even dimly aware of. This is through no fault of our own: most "conscious activity" is unconscious, and we have no access to it.
Over the millennia, we've identified a few kinds of thought, but we're quite far from understanding them, and there are clearly many other kinds of thought, mostly very far from our conscious awareness, which enter into our every living moment.
One of these the is the application of feeling. This is described in Christopher Alexander's four volume The Nature of Order, but essentially, in order to tap into our ability to create really good structure, which resonates deeply with people, we need to follow a process where we ask ourselves whether choice A or choice B has deeper feeling. I would put 'deeper feeling' in quotes, but in order for this technique to have good results, you need to ask it, of yourself, with as little interference as possible, and as honestly and simply as possible.
So, what might be going on here?
This technique seems to allow us to recognize (I almost said 'resonate') with structures effectively shaped by natural laws: the still poorly understood biophysics of living organisms. The conscious mind, and hence much of the subconscious mind, can interfere with our ability to see coherent, well-balanced, natural geometry. But 'the shortcut', an honest response to the question 'which has more feeling?', seems capable of resolving many issues like 'which of these is most profound?' This can be very useful for an artist trying to unleash their full human potential, and for an engineer trying to create a really good machine, program or user interface. It even enters into scientific work: which is the best way to represent a theoretical or experimental result? The one which has the most feeling, the one which is simple, lucid, elegant, and beautiful. This can be a guide to improve your work as you do it. Advanced mathematics, and even simple arithmetic, would be almost impossible without it. We use this criteria, to some degree, all the time. Just not enough. And we allow other forces to interfere when we shouldn't.
Now, this is an assertion. You can read The Nature of Order and test it yourself. I should point out that it's not really a training manual, or a training course, but more of a long explanation of the technique, its basis, and what it might mean. Showing someone how to apply feeling is something, I find, that is best communicated person-to-person. I'm not sure why.
Do you believe this? Many artists do, because they really need to use this technique explicitly throughout the day, to do their best work. Engineers have a harder time believing it, primarily because their working environment was formed with this shortcut only in some degree, but not often enough, and not explicitly enough. So we spend a lot of time wrestling with new, rather pedestrian computer tools that never seem to offer much of an advantage to engineers-as-human-beings. The programming environment designers didn't know how to apply feeling, and certainly didn't try to facilitate its use among their users.
The hard sciences have very little to say about the application of feeling. It's too complex a topic. Remember, physics is successful because it deals with the simplest imaginable phenomena. Chemistry is more complex. Biology even more complex than chemistry. And human biology is just off the scale ... we know much less than most researchers want to admit. The biology of human thought, which overlaps with psychology, is so complex that most of it is still 'soft science'.
So, it will be a very long time before we understand the application of feeling as a part of the human mind. We're not even sure what understanding it might look like. We can certainly see what kinds of structures are produced, and effective to people -- but they are hard to characterize the specific geometry of, at least in a way that a computer might recognize it. Exploring the geometry is a primary topic of The Nature of Order, using a technique that's not so different from exploring universal grammar in biological linguistics.
We could probably get a decent fMRI result of the state the mind enters when this evaluation-of-feeling is taking place. It's hard to see which questions to ask, after that. We could do more fMRI's to differentiate the application of feeling from other kinds of mental activity, essentially asking "how often does the feeling-evaluation-faculty enter into other mental processes?"
But I'm mostly interested in how hard it is for engineers to use this technique, even when it is done within a perfectly reasonable research context. It could have been used to 'rate' patterns in the software patterns movement, but it wasn't, even though rating is a prominent part of the original book A Pattern Language, and a critical tool in its predecessor, The Oregon Experiment.
This has always troubled me. User interface designers have no trouble asking themselves this kind of question. Why do programmers, or programming-tool developers? If we're ever to make any progress with software tools, engineers will have to be open to asking and answering these perfectly reasonable questions about their interface with the machine.