From the Stoics I'm attaching most to the 'happy accidents'. That in painting, as in life, there are things that happen that are (more or less) out of our control, and that we ought to accept and work with them. Trying to fight them in the painting will lead to a muddle of color, to frustration and ultimately to a less successful life (in the eudaimonia/flourishing sense). He doesn't go quite as far as to say to be unattached to the world or your painting, but just to accept what might happen.
In the Asian realm, one thing that Bob talks about quite a bit is the power a painter does have in 'their world' from simple actions. The whole technique is intended to make paintings that look like they take a great deal of effort but in truth can be done in a half-hour. One specific reference to power that stands out is when he is making mountains and uses a single stroke of highlight color to move a mountain from the foreground to the background. In addition to thinking it's the coolest thing since the invention of oil paints, he often mentions that we have the power to "move mountains". I'm reminded of rhetoric in the Huainanzi that roughly says that incredibly simple actions can often have a huge effect, much more so than forced, major ones.
I know I'm glossing over a lot and summarizing quite a bit with these. For those familiar with these (or other) traditions, am I totally off base here? Do you have more to add? I don't think he was doing it on purpose, not that he was unintelligent just that he wasn't concerned with being philosophical.
via Reddit: Link