I was watching a documentary about the Hong Kong Port Authority and was amazed at how an open expanse of water, traversed by numerous ships, was configured into nautical highways (which are only defined in the control towers' radar screen) with sea traffic controllers guiding the ships, much like air traffic controllers guiding airplanes. There were no buoys to mark where you should make a turn, much less visible lanes to direct the path of the ship.
I think that life is a lot like that, maybe minus the full-time traffic controllers. The paths or lanes are pre-defined by society, not by conscious acts of defining the right track but simply by an act of social habit which reproduces existing tracks. There are no manuals in life for getting from here to there but those within particular fields have a sense of what those tracks are. To some extent, these tracks are reflected in the sequential series of rewards associated with following the right track.
In the academe, for example, the track is well-defined. Bachelor's degree, master's degree, Everything But Dissertation, Ph.D. Progress along each step is rewarded with both increasing economic remuneration and increasing cultural capital. In the middle of it all there are the rituals of attending academic conferences, conducting research, publication, presentations at academic conferences, being appointed to administrative positions or elected to positions in professional organizations.
The tracks we follow, much like the track that is followed by those in the academe, are all socially constructed and are socially reinforced. They are socially reinforced by those who follow the track (whether obediently or grudgingly) and they are socially reinforced when we encourage or bully others to follow the track (ex. by making them start their M.A. or PhD, or by making them finish their thesis or dissertation). Sometimes people are fired because they do not follow the track or take too long to finish the track. This is a not too subtle reminder to others to stay on track and keep the pace.
In all this activity, the tracks themselves become part of our taken-for-granted. It is assumed that an academic, no matter how brilliant, needs to secure at least an M.A. and at the very least make an effort to securing at least a Ph.D. One can make a conscious decision about where to take graduate studies but the fact that graduate studies needs to be taken is taken-for-granted.
The conferment of a graduate degree may have very little to do with a person's actual competence, especially in teaching. There are some teachers without M.As who are simply brilliant teachers and there are some teachers with PhDs and post-docs who do not know how to teach. (Thankfully there are those who have PhDs and are brilliant teachers) One particularly (and universally acknowledged) brilliant teacher I know who has not yet finished his PhD comprehensives lamented to me once, "Can't I just teach?" But within the field, actual competence matters less than getting past the various pre-designated posts along the socially sanctioned track.