1 00:00:00,240 --> 00:00:03,740 So let's look at an example of deductive reasoning. So Premise A, is all mass 2 00:00:03,740 --> 00:00:09,672 creates gravity. And Premise B, is all objects have mass. Therefore, all 3 00:00:09,672 --> 00:00:14,523 objects create gravity. Because if all mass has gravity and all objects have 4 00:00:14,523 --> 00:00:19,710 mass, then they must create gravity. Notice that the logical conclusion has to 5 00:00:19,710 --> 00:00:24,811 be true if the 2 premises are true. We know, however, that this type of 6 00:00:24,811 --> 00:00:28,587 reasoning can lead to correct conclusions only when the general premises to 7 00:00:28,587 --> 00:00:34,360 which they are based are true. Let's look at another example. Premise A,is I 8 00:00:34,360 --> 00:00:40,322 don't know math. Premise B is, I can't learn math. Therefore, I shouldn't even 9 00:00:40,322 --> 00:00:45,050 bother trying to learn math". We see, here, that this reasoning leads to a 10 00:00:45,050 --> 00:00:50,330 false conclusion, because premise A is false. And so is premise B. So, even 11 00:00:50,330 --> 00:00:55,306 though the argument is. Easily structured in the same way. One leads to an 12 00:00:55,306 --> 00:01:01,558 accurate conclusion, and one, this one, does not. Deductive reasoning is what 13 00:01:01,558 --> 00:01:05,878 scientists use when we make predictions for our general goals. Now let's go to 14 00:01:05,878 --> 00:01:07,900 Susan and talk about inductive reasoning.