I was trained as a mathematician, so on one level the title of this post really bothers me.

On the other hand, it is true-at least partially. It is also true that mathematics is an art as well. An art, grounded with rules, laws, theorems, and postulates. But even “art” has rules, rules of color, composition, and form. Rules can be worked with, or worked around, and usually therein lies the “art.”

I’ve been working on an article on a family in Missouri in the 1860s. The family really doesn’t matter. Putting together the material does. I have a conclusion, soundly reasoned, but which could (if new information arises) be shown to be incorrect. Hopefully that doesn’t happen. The logic lies in the validity of my conclusion and the soundness of my argument.
Where is the “art?”

The art is in constructing the argument in a fashion that makes sense to the reader and sense to the writer as well. The art is the very process by which evidence was analyzed, summarized, and synthesized into a conclusion. Genealogists are not boiling chemicals in test tubes, waiting for a specific reaction at a specific temperature. Genealogists are not mathematicians looking to prove a great theorem by induction or some other method. 
Genealogy is an art and it is a science. Some days it is more on than another. 

I’m not certain which day it is today.