I would also note that it is worthwhile to be wary of the "double tax" rhetoric. At best, it is an ideological point of dubious worth - i.e., that there is a moral injustice in taxing some money twice. How much moral injustice? Well, I don't know - how much worse is it really than the idea of taxation itself? If I'm okay with being taxed, I'm probably more concerned with how much I'm being taxed, how fair it is compared to other folks, etc., than I am with whether it's two smaller taxes vs. one larger one.
At worst, though, it's a shell game that distracts from what's really going on in the tax code. In everything I've seen, taxes occur on transactions, not on stored wealth. So it's pretty easy to point at any income and outflow and argue that the money itself is being taxed twice. One could argue that the sales tax is a double tax - I'm paying income tax when I earn my paycheck, and then sales tax on the same paycheck when I spend it on groceries.
Anyway - in your example, the non-investor pays taxes on, let's say, $50k of income, then buys a car with it. The investor pays taxes on, let's say, $40k of income, invests it shrewdly, then takes the final $50k out of the investment and buys a car. The non-investor pays income tax on his $50k; the investor pays income tax on $40k, then capital gains on the $10k he made on the market.
The government could have easily taxed the investor on the entire amount withdrawn. That would obviously be pretty dumb, though.
At worst, though, it's a shell game that distracts from what's really going on in the tax code. In everything I've seen, taxes occur on transactions, not on stored wealth. So it's pretty easy to point at any income and outflow and argue that the money itself is being taxed twice. One could argue that the sales tax is a double tax - I'm paying income tax when I earn my paycheck, and then sales tax on the same paycheck when I spend it on groceries.
Anyway - in your example, the non-investor pays taxes on, let's say, $50k of income, then buys a car with it. The investor pays taxes on, let's say, $40k of income, invests it shrewdly, then takes the final $50k out of the investment and buys a car. The non-investor pays income tax on his $50k; the investor pays income tax on $40k, then capital gains on the $10k he made on the market.
The government could have easily taxed the investor on the entire amount withdrawn. That would obviously be pretty dumb, though.