This is something that I have discussed with a few of my friends and family: Is both Writing and Painting a physical skill? Physical Meaning, that it is an action in which quality is based on physical aptitude.

I believe that Writing is a mental skill. The words are formed using the thought process, the paper or computer is just a medium in which the product is transmitted.
Painters however, must stress on brush strokes, shadowing, ect. If the artist is not careful, the finished product will not be very good.

Well, obviously. You can't write if you can't move your hands. If you can't move your hands, you can't write- or type. Which is obviously based on a degree of physical aptitude.
And uh, painting without thinking? Some work that's gonna result. Did you know that oil paintings can have as much mistakes you require, because you can just paint 'over' the mistakes? Most professional painters paint in oil.

But more importantly, can you please develop your topic a bit more? To me, It's not a subject inherent with lots of things to talk about. How is this in anyway, serious?

The ability of someone to write would be hindered much less than someone who were a painter, if their physical aptitude or coordination were poor. An artist requires both finesse of the hands, as well as great mental training and knowledge. You can't be a great athlete and just start drawing or painting out of the blue and be perfect. To become a good painter, you have to learn how to really see how things are, and learn how to see those things on your blank canvas before you can draw them. Painting is a very mental thing indeed, but requires a certain amount of finesse before possible.

Writing on the other hand, is a very mental thing and requires very little physical finesse for a writer to write, especially nowadays that we have the keyboard. One thing I want to stress, is the fact that not everybody can write novels, even with enough time to do so. A lot of people believe they could write the next Lord of the Rings trilogy if only they had the time to do so; writing is not nearly as easy as it sounds, and writing requires much more than just enough spare time. I wish I knew the link, but I had a great source about this that was actually pretty funny to read

Painting is mental. Just ask a savant.

This is not an SD topic. (any longer)

>> moved

Edit:
tl;dr @ Cecil v

Painting, I'd think so. It takes a steady hand and such to do it I think.

Writing? No. As long as it's legible then w/e. You can type if nothing else.

Talk to anyone who paints ... Everything to them is very visually represented in their minds. Even if you have some sort of super-human control over your hands/brush strokes, you'd still lack details found in the works of great artists because you'd probably overlook something(s).

It's more mental than it is physical. Writing is more complex than just randomly scribbling. You actually have to think about what you're writing (unless it's non creative and more of a redundant task that you do)

Painting is also more mental. You have to bring out what you feel onto the painting. Add your own creative touches and stuff.