In his book “The Wisdom of Insecurity: A Message for an Age of Anxiety“, Alan Watts argues that to define a process or a phenomenon is not the same as to understand it. Of course, it is possible to become lost in the semantics of what the definition of “understanding” is, but in general, I believe this viewpoint provides a great insight.
Even though we can define something, we often lack the deep understanding of it until we can experience the concept in question. In kendo, for example, it is almost trivial to memorize the names and superficial biomechanical descriptions of various techniques (waza). However, the understanding of the implications of the techniques develops gradually, through practicing them in multiple matches (shiai) and training sessions (keiko) against different opponents. I suppose, a similar difference exists between defining the various mechanical processes and artistic concepts that are involved in extracting a piece of music from a violin and actually playing it. Practice, as in physical doing, is the key word here.
By extension, the same principle applies to photography. It is not sufficient to mentally grasp the concept of camera shake, for example, that is caused by excessive rate of pressure on the shutter release button. To really understand the effect in conjunction with various focal lengths, shutter speeds and lighting conditions, one needs to practice rolling his/her finger over the shutter button hundreds of times and examine the results.