Yes, they are. The people who own and run Google and Facebook and Amazon didn't magically get "capital" from nowhere. They used their skills, and turned those skills into huge amounts of money. In other words, they understood what capital they owned, and acted to maximize their return on that capital.

If you insist on refusing to view your own skills as capital, you're just giving up the chance to maximize (or at least improve) your return on that capital.

Following that, capital is potential energy.

Skills are the ability to meet spec quicker than someone who has to learn as they go. Sounds like potential energy to me. Since capital acts like potential energy, it follows that skills are capital.

If I invest $100 dollars in very safe investments today, what will it be worth in 50 years? Now, invest in your skills for 50 years, what's that going to be worth?

I get what you're saying, you're using the 'human capital' social science-y definition.

I don't really get why you're using that definition, though. Was the person you responded to not clear as to what he meant by capital, so you misunderstood and thought it was human capital? Or did you just want to derail into a semantic discussion?

Okay, so what are skills if not capital assets?

Knowledge.

And knowledge is power, comrades!