Transcript for:
Exploring Logic and Critical Thinking

Hi everyone, welcome to module 4. You're getting through logic and critical thinking and hopefully you're starting to have fun with some of it. This week we're going to talk about a couple of terms, sponge versus panning or panning for gold thinking. And we're going to start looking at types of arguments there are.

Deductive and inductive are the two main types of arguments that there are. These next couple of modules, we'll look at deductive. Later, we're going to figure out how to analyze whether both types of arguments are good or bad using different terms.

But right now, let me just tell you a little bit about sponge versus panning for gold thinking. And then we're going to talk about two specific types of deductive arguments. Make sure that you read through to the end of chapter one. chapter two in your Dowden book.

That book goes through a little bit of deduction and implicit premises, implicit conclusions. Those are important to consider. When you get to the quiz that we have this week, I will also draw from there and then some things that we had from last week too. All right, let's get going. So as I said, We do critical thinking because we're trying to find more truth.

The proverb I'm sharing here with you says, deep doubts, deep wisdom. Little doubt, little wisdom. That just means if you're accepting everything you're told, you might not be that wise. Hey, if you...

Hang out with people that always, always tell the truth or have all the knowledge that there is. Great. But most likely at some point, we're going to be on our own or driving in the car to work or school.

And we're going to hear some news or an advertisement. And we have to doubt. We have to do deep doubting in order to find the truth often. As many of you have been mentioning from week one.

in your Padlet as well as last week in terms of continuing to think, how did I find this information? And was there ever a time I didn't have all of the information? What did I do?

So we're going to continue to think about that. A sponge, what do you think a sponge does? A sponge absorbs things, right? It doesn't go out and actively seek information.

It sits there and lets it all come in. It's not to say that sponge thinking or sponge information isn't necessarily always good or accurate, but it's the easy way to get information. Maybe you watch videos or listen to a professor speak and you just let it wash into you. You absorb it.

It's a little bit different though from the panning. Gold panning is different from sponge thinking. Okay.

Panning for gold takes a little bit of work. If you've not ever been gold mining or trying to find gold, you have to dig. Sometimes you have to make an explosion or you go to a creek and you shake through rocks.

That's how gold mining works. It's active. It's not passive like sponge thinking. It's very active and it takes effort.

Panning for gold literally means searching, digging, shaking out which is false, getting rid of the false, and holding on to what is true. Okay, in the last module, we looked at premises and conclusions. I want you to keep thinking about those and see if you see any.

We will take a step farther really soon and then also analyze how do we know if premises are true. But for this module, again, I want to start talking about deduction. Deductive arguments are arguments that follow a form, and if the premises are true, the conclusion has to follow just from the way the form is set up. There are five types, and this week we're just going to talk about the first two. So even though we have definitions, math, and three types of syllogisms, and you're welcome to look at this resource.

For just purposes of module four, I want you to concentrate on definitions and math. Why are those deductive arguments? I'm going to tell you. An argument from a definition literally just means we're going on the meaning of a word, so or actual terms, or a legal rule.

That's how we prove that an argument, a conclusion, necessarily follows. I'm going to give you some examples to make this easier. Here's an argument from definition. This has to do with the tort, in other words, injury in legal terms of defamation.

Defamation occurs legally when someone writes or says something harmful and that causes negative outcomes for a person. For the reason that, are you seeing the premise indicators here? Mr. Joey Smith told everyone Susie was an axe murderer. She lost her job, but he knows she's not an axe murderer.

So he lied on purpose. That is the legal defamation. definition of defamation. Therefore, he's guilty of defamation based on the definition, that actual rule. I love arguments from definitions because they're easy.

It's easy to figure out if they're true or false, right? Or if they're good arguments or bad ones. Let's look at another one. And just so you see, we'll go through and look at these. Are the premises true?

Yes, the premises are true here. If all those premises are true, the conclusion could not be false. There's no other ending that we could get to.

He's guilty of defamation. You may have heard recently of a large defamation case in the news, a couple of them, because the legal definition of defamation was clearly proven. Someone we all know and have heard of was guilty of defamation.

spamming another person. Okay. That's how that works.

Here's another example, maybe closer to home. Philosophy professors are diligent and committed. I only need one premise there because I know if I know the definition of diligent and committed, I can conclude philosophy professors are hardworking and dedicated.

Diligent means hardworking. Committed means dedicated. So there's my... Argument from definition.

See how that works? You just find the words that you're trying to define, find an actual real definition, then you've got an easy deductive argument from definition. Math. An argument from math is also deductive because if the premises are true, the conclusion has to follow. And these are also a type of rule, an argument from a rule.

We all know the rules of math or subtraction, and if we're following them correctly, arguments from math are easy ways to prove things. Here's an example. Cassandra had two dogs at the park yesterday. Today, she left one dog at home. What's my conclusion?

Easy. Not a trick. It follows that. Cassandra has one dog at the park today. Just one dog.

Right. So you can say one plus one equals two or two minus one equals one. Argument from math is deductive argument, because if premise one and premise two are true, there could be no other conclusion.

OK. That's how that works. Here's written form.

If you want to look again and see that I have a conclusion indicator there, I've put that in bold. Let's see if we have another one. This is, I'm putting it out here again because I want to show you and remind you very emphatically. If the premises are true, the conclusion follows. That's the case for all deduction.

All five deductive arguments that we will learn, whether it's math, definition, or the three syllogisms, which we'll look at in the next module. If the premises are true, the conclusion necessarily follows. important thing to remember.

Here's the last one. My tax guy said I'm going to have to pay $2,000 more than last year. Last year, I had to pay $6,000 in taxes. So you can guess what the conclusion is. $2,000 more. If you know I paid $6,000 last year, what's the conclusion?

Hopefully this is easy math. $8,000. Thus, my tax bill will be $8,000.

Awful. Here again, if the premises were true, the conclusion would follow necessarily. Easy? Hopefully you're saying yes. Deductive arguments from math and definitions are easy.

So what about being a sponge and what about panning? We have to think as we go through all types of arguments throughout the semester, whether they're deductive or inductive. How do we prove whether the premises are true or not?

We're going to keep asking. You can't just be a sponge. You have to actively search. So in the last example, do you know if I paid $6,000 in taxes last year? It doesn't matter for the example, but if I were trying to prove something to you and I lied, it would still be an argument from math.

but it would be an argument that you would not want to accept if you found out I was lying. That takes more work, hence the picture of the panning for gold. We have to work a little bit to find out what the premises, the truth value of premises are.

Don't worry about that too much. We're going to do that as time moves on. I hope you're having fun. Have a great week.