The search for maximum simplicity.

"Numerous factors compel the scientist to revise constantly his conceptual construction. Apart from general cultural predisposi- tions, conditioned by specific philosophical, theological, or politi- cal considerations, the three most important methodological fac- tors calling for such revisions seem to be: (1) the outcome of further experimentation and observation, introducing new effects hitherto unaccounted for; (2) possible inconsistencies in the logi- cal network of derived concepts and their interrelations; (3) the search for maximum simplicity and elegance of the conceptual construction. In most cases it is a combination of two of these factors, and often even the simultaneous consideration of all of them, that leads to a readjustment or basic change of the con- ceptual structure." (Max Jammer)

(3) is definitely related to the drive for abstraction when it comes to Mathematics. One could wonder why we have (3) as a goal. But the answer is simple: because it allows our poor limited intellect to make new progress while tackling increasingly complex subjects by ... making them conceptually as simple as they possibly can be.