Learn about Deductive and Inductive Reasoning

TenMarks teaches you about deduction and inductive reasoning.

Learn about Deductive and Inductive Reasoning In this lesson, let’s learn about deductive and inductive reasoning and what’s difference between the two. We’ll do a couple of problems but the first one wants us to determine if the conclusion below uses inductive or deductive reasoning. First, let’s understand the difference between the two. Inductive reasoning is what we determined to be a pattern or rule based on examples that we see or a few sets of data. Deductive reasoning is based on logic and facts and statements given to us. So let’s look at the examples given to us. It says there’s a myth that an eel skin wallet will demagnetize credit cards. So, the conclusion is that the eel skin wallet will demagnetize credit cards because the skin of the electric eels used to make the wallet holds electric charge. So, the hypothesis is that the skin of electric eels holds an electric charge. This is the myth, skin of electric eels holds an electric charge. This is the second part of the statement says, that the eel skin wallet will demagnetize credit cards. This is the hypothesis and this is the myth. The myth says the skin holds an electric charge. Based on this, the hypothesis is that the eel skin wallet will demagnetize credit cards but the other part of the statement tells us that eel skin products are not made from eels. So, this is the hypothesis and the conclusion is the myth cannot be true which means that the eel skin wallet will not demagnetize the credit cards. So, let’s analyze this. Are we using inductive or a deductive reasoning? Well, inductive reasoning, we would be using examples. Here, we’re using logic and facts. We’re basically saying the hypothesis is that eel skin wallet will demagnetize credit cards and it comes from the myth that the skin of eels holds electric charge. So, let’s say this is true but since we know that eel skin products are not made from eels, this is not true. So basically, what we’ve proven is eel skin wallet will not demagnetize credit card, this conclusion is true because the product eel skin wallet is not made from eels and therefore it cannot hold an electric charge anyway. Since this is based on logic and facts, this is deductive reasoning. I did use that since an eel skin wallet is not made from eel skin then there’s no question of a demagnetizing cards because it does not hold electric charge. Therefore, this is deductive reasoning. Let’s use the second example. Part B says all the students in Daniel’s Algebra class are juniors. And john takes Algebra. So that what we know is John takes Algebra. And we can say that all the other students in the class are juniors. These are two statements given to us. These are two examples given to us. Just some data sets. But it is possible that John takes Algebra with the juniors but himself is not a junior. John could be taking an algebra class with the 50 juniors but himself may not be a junior. That’s an example that I can come up with which basically says that John may not be a junior. So, if this statement is true then we based it on inductive reasoning, not logic. We assumed that because John’s class has all juniors then John himself is a junior. That’s based on a certain set of data that we have but not all the facts. So, this is inductive reasoning. Now let’s try part two. Part two wants us to draw a conclusion from the statement given to us. Statements are if a polygon is a triangle then it has three sides. If a polygon has three sides, it’s not a pentagon and polygon Q is a triangle. So, if polygon Q is a triangle then polygon Q has three sides. And if it has three sides then polygon Q is not a pentagon. That’s the conclusion. Polygon Q is not pentagon because if it was, it wouldn’t have three sides. If a polygon Q is a triangle, I can use the statement to say that it has three sides and if a polygon has three sides which is related conditional then it is not a pentagon. So, polygon Q is not a pentagon is the conclusion that we were looking for. So, what we learned here is inductive reasoning is based on certain facts. John takes Algebra, all of his classmates are juniors, so I can induced that John must be a junior but this can be proven false by a simple statement. What if John was in the class but not a junior, he could be senior taking an Algebra class with the other juniors. If I can find one example then I can prove a statement wrong which was based on inductive reasoning but statement based on deductive logic or deductive reasoning could not be proven false. So, in order to prove that statement is absolutely true, we must use deductive reasoning.