Flannel Jesus wrote:Yes, I think that's an important point: deduction only works when the premises are true.
Let's say there's a guy named Socrates, and as far as we know, he's human, and he's about to drink hemlock. Let's deduce what will happen when Socrates drinks it:
Socrates is human.
All humans die upon drinking hemlock.
Therefore, Socrates will die.
Now, this indeed is a valid syllogism, but if you really think about it...well, it doesn't really prove anything. What if Socrates isn't human, but a robot from the future that's immune to hemlock? What if Socrates is human, but has some rare mutation that makes him immune to hemlock? If either of those premises turns out to be incorrect, then this syllogism actually doesn't say anything about reality. The limit of deduction is the limit of the truthfulness of the premises.
However, it would definitely be within reason to say that he'll most probably die. If we were two Greek guards from the time of Socrates, I'd bet on his death.
I think that one is actually more an induction. We see that people who drink hemlock die. We don't have counterexamples. So we make a tentative rule. Hence the probably. You've presented it as a deduction, with a missing step that Socrates is about to drink hemlock. But in fact it's more of an induction situation. And, of course, someone out there, like Rasputin, would probably survive that hemlock.