Unless you're involved with thinking about what you're doing, you end up doing the same thing over and over, and that becomes tedious and, in the end, defeating.
The idea becomes a machine that makes the art.
In conceptual art the idea or concept is the most important aspect of the work
Artists of many diverse types began using simple forms to their own ends.
Artists teach critics what to think. Critics repeat what the artists teach them.
The idea part is simple but the visual perception is complex.