"Now, what that means is that there is fundamental indeterminacy from quantum mechanics, but besides that there are other sources of effective indeterminacy"

Murray Gell-Mann's quote is referring to the principle of indeterminacy, which is the idea that particular events or outcomes can not be anticipated with certainty. In the quote, Gell-Mann is saying that quantum mechanics gives essential indeterminacy, suggesting that the behavior of particles on the quantum level is unforeseeable. Nevertheless, he is also recommending that there are other sources of indeterminacy, which could be related to the behavior of larger items or systems. This might include things like the weather, the stock market, and even human behavior. Gell-Mann's quote is stressing that indeterminacy is a natural part of the universe, which it is not limited to the quantum level.