Ultimately I agree with the conclusion, but the logic of how you're getting there seems flawed in that the question you're asking doesn't add any value. The fun

Ultimately I agree with the conclusion, but the logic of how you're getting there seems flawed in that the question you're asking doesn't add any value. The fundamental question is whether all marbles in a bag of n black marbles are black for all values of n including 0. If the answer to that question is yes, then the answer to your question is yes. If the answer is no, then the answer to your question is "yes except if it results in n=0".