Induction and Deduction

 Deduction and Induction

Induction and Deduction are the two biggest tools the philosopher has in their kit for discerning what truth is or what it is likely to be. They can be hard to get a grasp on though.

Deduction is the study of the validity of the form of an argument. Induction is the study of the likelihood of an argument's conclusion assuming that its premises are true. Deduction is about how well the form preserves truth, and induction is about probabilities.

A Brief Introduction

    It's one of my greatest pet peeves in life that you have to pay for knowledge. So much of knowledge is inaccessible unless you have money. I have personally been both the victim and the beneficiary of this model, and can see at least some of its merits. Yet, I still wish the world of academia was more accessible to the people as a whole. 

    

    I'm a trained researcher. Trained in statistics, data gathering, and data analysis. I specifically focus on psychological phenomena as I find that the most interesting science. What I have to say here applies to all sciences as they all use very similar styles of formatting and publication. When publishing papers it is looked down upon to state what different statistics mean.

    There are good reasons for this. It keeps papers shorter, and prevents meaningless rehashings of the same thing over and over. However, an unfortunate side effect of this is that it also prevents the average human from actually understanding what a research paper is trying to say. 

    Unfortunately, most academic publications do that or similar things. I remember the first philosophy paper I ever read. I was so confused and never would have continued if it had not been for my professor who spoon-fed the basic information to me and the rest of the class. My hope is to make that basic information more accessible to people by breaking the information down into easy-to-understand ideas. 

    We'll start with the deduction and some of the important information there. Then we'll talk about induction and the basics there. As a brief note, there seems to be an idea that floats around every couple of years. It's on identifying induction and deduction. The idea is that deduction goes from general to specific and induction goes from specific to general. 

    

    That is a gross overgeneralization. It's a really bad way to categorize the two studies, and it's actually completely wrong. Hopefully, why will be made clear after reading this article. To be fair, this idea does exist outside of philosophy and it'd be silly to try to standardize information across all disciplines (though I do believe that would be a good idea and should be done. I just think it's silly to expect that at this moment).

Deduction

    As mentioned above, deduction is the study of the validity of the form of the argument. That's a pretty wordy definition and a pretty simplified, but hopefully, it catches the idea enough to be useful. One of the most basic ideas of deduction is that it preserves truth. An idea that can be demonstrated by the use of something called a truth table. Something I'll talk about in another post. 

    

    Let's pretend real quick. Your words form an argument. This argument forms a paper cup. If the cup is good it holds water. If the cup is bad, water seeps through it. This illustrates the idea of validity. The good cup is the valid argument, the bad cup is the invalid argument. The water in the cup is the truth value of your argument. 

    The purpose of deduction is to train you to be able to tell whether or not the cup is good. The property of good is validity. So if your argument is good, then it preserves truth. If your argument is bad, then it does not preserve truth. Good and bad here represent validity and invalidity, respectively. 

    Now let's talk about forms. Form is the philosophical term for equation. If your form is valid, it preserves truth. If it is invalid, then it becomes induction (probabilistic). In other words, if you use the right equation, you'll get the right answer. Much like math.

    There are a great many valid forms that exist. I'll cover some of the most basic and common, but validity is a property, not an argument. So it can be added to any argument so long as you know what you're doing.

    What validity means is that the conclusion of the argument is never false if all of the premises are true. So it is completely possible to create your own argument where this is possible. I'll show you how when I write about Truth Tables. 

    Briefly, some of the most common valid forms (or equations) used in philosophy. You have:

Modus Ponens

1. If A, then B
2. A
3. Therefore B

Modus Tollens

1. If A, then B
2. Not B
3. Therefore not A

Disjunctive Syllogism

1. Either A or B
2. Not A (or 'Not B')
3. Therefore A (or 'B')

Hypothetical Syllogism

1. If A, then B
2. If B, then C
3. Therefore, if A, then C

Constructive Dilemma

1. Either A or B
2. If A, then C
3. If B, then D
4. Therefore, either C or D.

    Remember, these are only some of the most common valid arguments. And remember that an argument being valid only means that the conclusion cannot be false if the premises are true. Validity preserves truth. Something that I'll demonstrate when we do truth tables.

Induction

    Induction is all about probability. It deals only with invalid arguments, that is, arguments where the conclusions are not always true even if the premises are. That's the big difference between induction and deduction. 

    The conclusion of an inductive argument does not need to be true even if the premises are. To illustrate this, let's consider the math equation analogy again. 

    Let's pretend that 2+2=4. In a deductive argument, 2+2 always equals 4. It's completely and utterly unchangeable. Nothing can and nothing will ever change that. It's a universal truth that 2+2=4. But, let's pretend that we live in a society that has not proven this unequivocal truth. Instead, we're trying to prove what 2+2 actually equals. 

    We're arguing, trying to figure out what 2+2 equals. One person says that it equals 1, another says 4, and another says 2. Because we don't have the tools to decide this in a sure way, this is now an inductive argument. All we can do is pick one of the three options and hope it's right. 

    It's a little crude, but that's the just of inductive reasoning. Basically, we have some information, but not enough to actually know what the answer is. We only have enough to make some good guesses. I'll do another post soon about the processes used in induction. 

Conclusion

    Hopefully, I've made it clear what the two disciplines are and aren't. That being said, there is a lot more to be said about them, and I'll be doing some more posts on that soon. Until then, be sure to ask any questions you have:)