00:01
So here we're asked to show if the argument given is valid.
00:05
So we know that the argument given has these premises and the conclusion is this.
00:11
So we're asked to use exercise 11 to show that it's valid and then to use table 1 of the rules of inference to show why it's valid.
00:23
So we can say that this argument is valid if we also say that the same premise, and adding and q if we add q as a premise would make conclusion r would make this new argument valid so let's say that they both are valid now how can we show this we'll do a step and reasons now we'll use table one the rules of inference to show why this is bad at so step one we'll use a process so we use if q, then u and t.
01:23
Reason, this is a premise.
01:29
Can't do anything just yet, so let's put another premise.
01:35
If u then p, another premise.
01:42
Now let's look back at the first step.
01:48
We know we could simplify this, so let's use one compound proposition in our simplification.
01:55
So if q, then you.
02:00
So simplification of one.
02:06
Step four, now we could use steps two and three.
02:12
So we could rewrite this as if p, then you, and if you then q.
02:21
So using hypothetical syllogism, if p or if q, then p, or if q, then p.
02:33
Reason, hypothetical syllogism using two and three.
02:48
Now step five, let's use the second compound proposition that we did when we simplified number one...