Forwarded on to me by a friend in the USA and certainly worth a read. Perhaps a few people posting here might well do to understand the subject a bit more

“Let’s study logic,” sounds boring and scary, doesn’t it? That’s really a shame. But, more than that, it silly! After all, almost no one studies logic anymore. How would you know if it was boring or not?

The truth is that logic is very useful. In fact, we all use it all the time; but, since most of us have never studied it seriously, we also make a lot of logical errors… for which we suffer.

LOGIC: SIMPLE AND IMPORTANT

Logic is the science of non-contradiction. That’s not so scary, is it?

The purpose of logic is to identify things that contradict themselves and are therefore not true. That’s it! (Well, there are a few specialists who make long, complicated formulas to expand upon it, but that’s really a separate subject.)

Self-contradictory statements have shown themselves to be untrustworthy so many times that anyone with sense works hard to avoid them. Why waste time on the equivalent of 2+2=3?

Logical argument is actually mechanical; mathematical, really. It uses structured thinking to explain how a conclusion has to be drawn from a given set of assumptions.

FALLACIES

It is possible to create arguments that at first appear to hold together, but that really don’t. We say that arguments of this type are based upon some type of fallacy. A fallacy is a deceptive word trick that makes a lie appear to be true.

It is important to be aware of logical fallacies because they are found at the heart of almost every deception you will ever face. That means that you hear them on a daily basis. A lot of these fallacies are still called by their Latin names. This is because they were first noted as examples of faulty logic a couple of thousand years ago.

The sad thing is that almost all the fallacies of logic have been known for a long, long time, and yet people get suckered by them every day. Why? Because almost no one ever teaches them!

We won’t go into a full list of all the fallacies here, but we will cover a few common ones, just to give you a feel for the subject. (We’ll cover more of them in future issues.) A fun game is to listen to political arguments and shout out the name of every fallacy. It ends up being very fast-paced because most of these arguments are completely full of fallacies.

Ambiguity

Fallacies of ambiguity are used to create a false conclusion by confusing the terms of the argument. Sometimes a term is used in a different way than you might assume, or sometimes tricks of language are used to suggest something false without actually stating it clearly.

By the way, when people talk about logic, they also talk about premises. A premise is anything that your argument presumes to be true. (The tricky thing about them is when they are assumed, but not stated.)

A very common fallacy of ambiguity is called Accentus. This trick works by placing an emphasis (accent) placed on a word or phrase, or choice of words, in order to say something without actually saying it. For example:

"He is telling the truth this time."

The implication here is that he usually lies. The really tricky thing about this is that the speaker never really says, “he lies,” so it’s hard to challenge his statement. Because this type of trick usually comes and goes within a few second, most of us don’t pick up on it very well.

Bifurcation

The fallacy of Bifurcation (also known as the False Dilemma or the Excluded Middle), works by presenting only two possible choices when many alternatives actually exist. People are very susceptible to this. Our minds seem geared towards thinking in these binary, polarized terms:

True/False, Right/Wrong, Black/White, Us/Them, and so on. An example is this:

Either you support the policies of our leader, or you are a traitor to your country.

This fallacy is used a lot, and it is obviously wrong: You can certainly love the country and still feel that the leader isn’t doing such a great job. In fact, if you really love your country, you’ll be a lot more concerned about a bad leader than someone who doesn’t care very much. Another example might be:

Anyone who doesn’t support this new pre-school program hates children!

In both of the examples above, there are many more possibilities than just the two presented. This fallacy is usually thrown at people with a lot of emotion and with a lot of speed. In most cases, we don’t have a clear idea of what is happening and don’t sort it out until we’re on our way back home. (But, maybe next time, you’ll be prepared!)

Fallacies of Source

This trick implies that the source of an argument makes it true or false. However, the source of a statement has no direct bearing on its truth. A proposition is not true because it comes from a respected source and is not false because it comes from a hated source. Statements are true or not true depending on how they match reality.

One common trick of this type is to say that something is right or wrong, depending on whether is it new or old. Here are two examples:

"It was good enough for my grandfather – it’s good enough for me."

"You’re not still using that old technology are you? Version 2.0 was released last month."

Axioms

An axiom is something you decide to accept as true, even though you can’t really prove it.

At first this might seem like a silly thing to do, but it’s necessary. Why? Because we don’t know a lot of things and can’t prove even more things. For example, our first axiom is that reality is, in fact, real. This is almost certainly true, but can we really prove that the world isn’t a cosmic video game? That can’t really be done without stepping outside of our universe. So, we accept, as an axiom, that what appears to be real, is indeed real. If we ever gain the ability to step outside of our universe we can verify this axiom, and call it either true or false. Until then, it is something we choose to accept without proof.

The way to do use axioms well is by saying this:

We promise to always remember that we just made it up. We’ll also try to reduce the number of things that we are holding in our mind as ideas we can’t prove. But we will give this idea the benefit of the doubt for now.

That is what an axiom is. It is something that we can’t prove and we know we can’t prove, but we act like it is true anyway. There’s nothing wrong with this, as long as we are willing to discard an axiom if we ever manage to prove that it is false.

Here is a small set of useful axioms that you might find useful:

Axiom #1 - Reality is Real

This has to be the most overwhelmingly accepted idea ever to exist on Planet Earth. In fact, it’s hard even to imagine an existence where this wasn’t axiom number one. We are 100% reliant on reality being real every time we decide to focus our eyes on something, take a bite of food, or even take a breath of air. The guy who actually believes that reality is not real lives in in a psychiatric ward.

Axiom #2 - Our Perceptions are Accurate

The knowledge we get through our senses is good, even though it is limited. When we see a rock, our perceptions are right, even though they may not tell us everything about the rock. X-ray, infrared or other forms of analysis may tell us things that our naked eyes cannot, yet that does not make our eyesight wrong - just limited.

To increase the usefulness of our perceptions, we mix them with reason. For example, merely seeing the sun go up and down makes it appear to be moving around the Earth, but appearance does not make the simplest explanation true. In this particular case, further observation and analysis provided a better answer.

Axiom #3 - Humans are Individuals

This is another one of the things that is so overwhelmingly held, that to think otherwise is hard to imagine. Why even bother to communicate if we are not separate beings? We would already know each other’s thoughts.

Axiom #4 - Reason is Our Best Tool

Reason has been deeply involved with almost every human advancements, and no other source has really come close. Even when inspiration provides some good clues, reason follows to bring the new thing into actual existence.

SO NOW…

You know logic!

Sure, there are more parts to learn, and there are formulas you can use if you like, but you’ve got the basic idea. Was that so bad?

Originally Posted by KeiranMac

Logic's great for arguments. The best method though is platonic dialectic; establish a common/accepted fundamental ground and follow the next logical steps from there, people with poorly constructed arguments tend to stumble upon their own fallacies that way until they find themselves agreeing with the opposite side of the argument and contradicting themselves.

And if you're feeling in a bit of a mischievous mood, isn't it fun doing just that to tie some people, especially those who're a bit pompous, up in knots Not that I'd ever dream of doing so I'd best add!