I think it's mostly a matter of Occam's Razor, Kolmogorov Complexity, the pigeonhole principle, etc. There aren't many clean, simple equations (relatively spea

I think it's mostly a matter of Occam's Razor, Kolmogorov Complexity, the pigeonhole principle, etc. There aren't many clean, simple equations (relatively speaking), compared to long, ugly ones. Each time you make an equation longer, you have a huge variety of choices for the new bits; if we take "ugliness" to include things like asymmetry, arbitrary constants, lack of relationships between the parts, etc. then there are more ugly equations than beautiful ones. It's more practical to look for simple, pretty laws since there are far fewer of them to try. Once we've exhausted them, we can try making things a little uglier, and seeing if that works; and keep incrementing. After all, if you have enough epicycles you can explain any motion you like (since you're basically taking a fourier transform)