It is generally possible to grow capital via investing or speculation.
But first of all, growing capital is not the same as income. The idea is that you grow capital and then you live from the capital gains. You never use you capital to pay your living expenses.
The other thing is: It being possible does not mean that you can do it. I think it requires a professional approach. That means you have to research strategies until you have a trading system that you know does work. And then you have to be able to trade by the plan, which most people can't do. It requires understanding your own psychology and take conscious control of your actions (in trading). Almost everybody thinks they are of course in control of their thinking and actions. Anyone who believes that is delusional.