lunarpower wrote:
as usual, the best way to explain is by analogy.
James doesn't grow facial hair. Therefore, he is probably no more than 14 years old.
choice (b): Every boy I know who is 13 or older can grow facial hair.
--> if this is true, then it actually supports the idea that james is younger than 13.
but, if we support the claim that james is younger than 13, then at the same time we're also supporting the (more inclusive) claim that he's 14 or younger.
this is a great example of "intuitive understanding"
if Ron authorized me to use the analogy, I'd use like this:
most of men over 70 have no hair left (= camps didn't have European goods after 1630).
so if you can't find any hair standing on the head of a man, he's probably over 70 (= if no European goods found in a camp, it may appear after 1630)
little note: a man without hair looks deadly fantastic! If you (readers) have no hair, don't worry. (high-tech will help)