The intent of this paper is to:
1. Classify various multi-objective optimization methods that are based on trying to attain certain desired values.
2. Make some critical comments on each class as a whole, and illustrate by simple graphically visualizable examples the potential problems or drawbacks pertinent to the general nature of each class.
3. Make some questions that could possibly “provoke” some further investigation.
As a result, the relative advantages and disadvantages of each class of these methods become apparent.