00:01
Okay, in this problem, we have to identify the logical form of each argument.
00:07
Identifies that if it's valid and then state what it is.
00:10
And then if it's false, we need to see what kind of error that we made.
00:14
So in this first one we have, if i get a christmas bonus, then i'll buy hysteria.
00:17
So that's p implies q.
00:19
So if i get a christmas bonus, p, then i can buy a stereo or will buy a stereo.
00:25
So p implies q.
00:26
And then it says, i will not buy a stereo, so not q.
00:29
And then we'll say, therefore, i didn't get a christmas bonus, not p.
00:33
Now, this is valid.
00:34
This is a perfectly valid argument.
00:36
It's called modus tollens.
00:38
Modus tollens.
00:40
And the way that you can remember modus tollens is that tollens is a negative argument.
00:46
And it means to take away.
00:48
So that's how i remember it, that t, the take away.
00:50
So it means not q implies not p.
00:53
It's a negative argument.
00:55
So that's how i remember it.
00:56
It's modus tollens...