1. Stella is a woman and she is mortal. 2. Joan is a woman and she is mortal. 3. Liz is a woman and she is mortal...etc How many instances of women being mortal do I need before I can come to the general conclusion that all women are mortal?

the short answer: you need as many instances as there are (or have been, or will be) women.

a longer answer: if what you're asking is how many instances do you need before it might be reasonable to infer that all women are mortal -- well there's no absolute answer to such a question (I would say). Partly it's about all such similar forms of reasoning -- in general, how many instances do you need in any inductive argument before it's reasonable to draw the general conclusion. Partly it's about the specific case -- what are the specific biological facts about womanhood (assuming that's a biological category) and mortality, which might govern how many instances are required before the general conclusion is reasonable. Partly it's a matter of social norms -- in the community you inhabit, how many instances will people require of you before they decide you are reasonable etc .....

the short answer has the benefit not merely of being correct but also being clear!

hope that helps ---

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