The concept of constraint satisfaction is crucial for understanding and improving human reasoning and decision making. A “constraint” is a condition hat must be taken into account when solving a problem or making a decision and “constraint satisfaction” is the process of meeting the relevant constraints. The key idea is that often there are only a few ways to satisfy a full set of constraints simultaneously.
Not all constraints are equal in importance, and as long as the most important ones are satisfied “well enough”, you may have reached a satisfactory solution. In addition, once you begin the constraint satisfaction process, you can make it more effective by seeking out additional constraints.
Constraint satisfaction is pervasive in part because it does not require “perfect” solutions. It’s up to you to decide what the most important constraints are and just how many of the constraints in general must be satisfied and how well. Moreover constraint satisfaction need not be linear: you can appreciate the entire set of constraints at the same time. And this process need not be conscious. “Mulling it over” seems to consist of engaging in all-but-unconscious constraint satisfaction.
Finally, much creativity emerges from constraint satisfaction. Creativity can also emerge when you decide to change, exclude, or add a constraint. Perhaps, paradoxically, adding constraints can actually enhance creativity, – if a task is too open or unstructured, it may be so unconstrained that it’s difficult to devise any solution
Stephen M. Kosslyn
from This Will Make You Smarter