Investment science and art - where is the intersection?

Science is what we understand well enough to explain to a computer. Art is everything else we do.
- Donald Knuth, computer scientist

The same could be said for investing.  There is the portion of investing that can be rules-based and explained to a computer. It could be the Fama-French model of betas. It could be a set of rules for finding trends. It could be the risk management that measures portfolio volatility.  However, this is often not enough to generate high returns. 

Advanced investment science now is the revolution in smart beta, but even if we can decompose the return of a fund through smart betas, there is still a lot of the variation that cannot be explained. This is caused by the art of investment management. It is the job of investment analysts through their due diligence to make sense of this art and find the unique intersection between it and the science of investing.