There is always going to be some degree of uncertainty with any action. Just because a meteor can fall on your head if you walk outside doesn't make it a gamble to do so. There's a fine line between investing and gambling, but the extreme ends of the spectrum should be obvious.

I'd argue that the difference between investing and gambling is that gambling has known negative expected value, whereas investing is uncertain. If it is not known that the outcome of a gamble has negative EV, then a reasonable case can be made that it is an investment.