There are times when the lives of assistant professors must be miserable. Given the prestige of the Harvard name only for a limited number of years, a junior faculty member has to recognize that he has only a miniscule chance to be promoted to the security of a tenured full professorship here.

The Faculty's action this week to make variable the fixed terms accorded to assistant and associate professors might serve to make the ordeal, though still fraught with insecurity, a little more pleasant.

By allowing departments to appoint assistant professors for three- to five-year terms, with the possibility of re-appointment for a total of six years, the Faculty has made it easier for a tenure candidate to demonstrate his abilities by giving him the possibility of an additional year to finish up a book or research project.

The question of how fairly to design a system giving fair weight to both the University's and junior faculty's needs has long been a complicated one.

It is unfair to a young professor to hold him in non-tenured position for too long a period of time without making a final decision about his qualifications to teach at Harvard. On the other hand, a University's extensive use of short-term appointments with frequent rotation of personnel introduces practices which one junior faculty member called "academic scab labor," by which universities could staff most of their teaching positions with low-paid young teachers to whom they have few obligations.

Harvard has recently tried to hold to a middle course in this area and this week's decision to drop rigidly fixed terms does not really make major changes in present practice.

Individual departments and junior faculty will now simply be permitted to make arrangements more suited to their specific needs.