Logic

To most people who have taken a course or two in logic at a university or something, what I'm about to say may or may not seem...sort of like a 'duh' statement.

Most people fail at logic.

If I ask the layman what logic is, they'll usually give me a situation that applies more to common sense than actual logic. It's not through any fault of their own though, I feel. The media has regularly used the word 'logic' when they really mean 'common sense'.

So what IS logic? Well, logic is a system akin to mathematics. It's a series of premises that are valid, and sound, that lead to a valid and sound conclusion. Altogether, these are caled 'syllogisms'. These conclusions can be something you believe to be true, or something you live by, or, can even act sort of like a puzzle, to test your logic skills. It's akin to mathematics because similar to how 1+1=2 and this is always true, Premise One and Premise Two will always equal the Conclusion given, as long as they're valid and sound. Here's a for instance:

1. Porn stars are human
2 Ron Jeremy is a porn star.
Conclusion: Ron Jeremy is a human.

Most people would like to say that they think logicaly, when the truth is, this isn't the case. COMPUTERS are logical, not people. People are notoriously ILlogical.

Again, it's not our fault we're illogical, it's kind of how we're wired. Sometimes our emotions just get in the way of logic. Here's a personal example from my own life

1. I define good to be anything that promotes the well being of others, and diminishes the suffering of others as well.
2. In a given hypothetical, if both my parents were killed, millions of people would be saved.
Conclusion: I should let my parents be killed in said hypothetical, if I want to do good.

Unfortunately, I could never imagine doing such a thing, I love my parents too much to sacrifice them, no matter how many people they'd save. This is a selfish illogical idea of my own that comes from a direct result of emotion, something logic doesn't really allow for.

So what does it mean to be valid and sound? I've used these terms a few times already but I never addressed what they mean. To explain, I'll use the opposite of valid, which, in logic, is called a 'nonsequitor'. A nonsequitor literally means 'does not follow'. For instance:

1. People exist
2. John exists
3. John is green.

Did you see the nonsequitor? The green part. Nothing about being a person, or existing, entails greenness. This may seem like a 'duh' statement, but it helps to illustrate the point. Next, we goo to validity. If something is valid, then all premises DO in fact, follow eachother, all the way to the conclusion.

Here's a common argument for the existence of god, to show how something can be valid.

1. The universe had a beginning
2. Every beginning has a cause
3. Every cause exists independent of the thing caused to begin.
Conclusion: The cause of the universe's existence had to exist independent of the universe. We call this thing God.

That, is a valid argument. However, and this leads into the next part of my little rant, it's not a 'sound' argument. A sound argument means that not only are the premises and conclusion valid, but they are all also true. Premise 1 and 2 and even 3, in the above 'god' logical argument are debateable, and until they are completely settled, are not sound. If they WERE sound, I would have to accept God's existence, as defined in the argument. Get it? IT would become as inarguable as a mathematical expression.

Now that I've explained logic, how it works, and the system, I'd like to conclude. When presenting an argument, I encourage the use of the logical premise/conclusion system. This makes the argument far easier to address, refute, or hell, even agree with, but I don't encourage the mocking of others who are logically inconsistent, or use bad logic. It's normally not their fault. Emotions get in the way, or they just don't understand logic.

There's my 2 cents. This rant brought to you by seeing several people in this forum accuse others of having 'bad logic'.

I agree with your post. I would add to it an idea of the reasoning behind a lack of logic.

To me, it seems that majority are raised against deductive logic and are steered more towards assumptive reasoning, or rather a logic that appeals to someones emotional comfort.

I would see no problem with that...if only there was some sort of balance. An example: you don't want to let someone who was just in a wreck think that dangerously speeding is ok by trying to appeal to there feelings. At the same time, however, you don't need to barrage them with a series of flaws in their thinking if their car just did a 180 through the air and landed nose down.

Actually being familiar with Boolean logic can also come handy. Boolean logic uses truth tables, that is you write up all possible combinations of basic statements, then you evaluate the expression. I'd like to highlight a frequent problem with implication:

Implication:

P => Q
p implies q

Example:
"If the river is narrow, then we can cross it quickly."

Truth table:

P=True, Q=True, P=>Q=True
P=False, Q=True, P=>Q=True
P=False, Q=False, P=>Q=True
P=True, Q=False, P=>Q=False

The important thing is, that an implication is only false, if the condition is true yet the implication is false.

Example:
"Even though the river is narrow, we couldn't cross it quickly."

So the frequent argument that if something is not true, then it's implication is also false is fallacious logic!
Look at the truth table, even though the initial condition is false, the implied condition can still take on true or false values and the implication itself is still valid.

Contrapositive:

What is implicit in an implication is its contrapositive:

From the definition of an implication we have:
P => Q = NOT(P) OR Q.

Example:
"The river is wide or we can quickly cross it."

Using the commutative nature of the OR operation we get:

P => Q = Q or NOT(P)

Using the double negation rule we get:

P => Q = NOT(NOT(Q)) or NOT(P)

Again, from the definition of an implication we have:

P =>Q = NOT(Q) => NOT(P)

Example:
"If we can't cross the river quickly, it's not narrow."

Negation:

The negation of an implication, is once again not what people normally use, but this is the correct logical result of an implication being false:

From the definition we have:

P => Q = NOT(P) OR Q

Therefore, taking the negation of each side of the equation, we have:

NOT(P =>Q) = NOT(NOT(P) OR Q)

From the negation law we have:

NOT(NOT(P OR Q) = NOT(NOT(P)) AND NOT(Q)
(This a De Morgan relation)

From the double negation rule we know, this is the same as

NOT(NOT(P)) AND NOT(Q) = P AND NOT(Q)

Therefore:

NOT(P => Q) = P AND NOT(Q)

So the negation of an implication doesn't implicate anything else!

Example:
For example, the negation of the statement

"If the river is narrow, then we can cross it quickly"

is the statement:

"The river is narrow and we cannot cross it quickly."

I have to say, the only thing that could have made that better would have been the use of tilde.
'
But I do wonder what boolean would say to the 'three gods problem.'

I think people are "illogical" not because they don't understand logic(though some might not). In general, purely logical reason just isn't useful in many of the situations we encounter. The part of your post that I quoted points this out.

In order to use logic, one must have premises that are knowable and agreed upon. This works great in math and computer science when you basically have free reign to choose whatever premises are useful and they are accepted for the purpose of whatever you are doing. However, I usually find that most debates I engage in revolve primarily around the validity of the premises used by the various parties. Usually when someone is accused of being "illogical," it has nothing to do with the process and everything to do with the premises in question.

The problem is that premises are not accepted at the universal level(though some are near universal). Even something like the choice to use logic can't be logically demonstrated to be a good idea using pure logic. We choose our methods and premises based on our experiences and what is useful to us. Can I create a completely unassailable proof that I exist? No, but the alternative premise(that I don't exist) is not at all useful to me and doesn't really match my experiences, so I don't worry about the pure logic and just decide that I do exist.

Logic works great when you are working within a system in which the premises are identified and agreed upon by all. In fact, I would guess that most premises, including many that seem quite simple, are held in dissension by significant parties. However, most situations we encounter do not match this description, and so logic is insufficient. It is a useful tool that we can use nonetheless, however the ability to be illogical is just as important in dealing with these situations.

I don't see it. We're going to have to agree to disagree. Btw I'm addressing your "We ought not use logic all the time" argument in here because in the other topic we've pretty much come to the agreement that I'm right if we define atheism my way ,and you're right if we define atheism your way, and while I believe etymological definitions are an accurate way to define words, you simply disagree. so we'll have to agree to disagree on that as well.



...Not necessarily. If I have a premise another person doesn't agree with, then they first have to show why their disagreement is logical before I have to change y premise to make it agreeable. If their disagreement is based on fallacies, they're the ones that are being illogical, and need to try harder, not the one putting forth the argument.



Considering that logic is used the exact same way as math, and logical arguments that are valid and sound DO count as 'proof' of conclusions...I think you're equivocating.



Yes, because at large everyone thinks they know what being 'logical' is. But the problem is, there ARE pre agreed upon Logical Laws that are inarguabl, there's different kinds of logic who all have axioms, like Boolean and Modal logic, that are pre agreed upon before engaging in discussion. However, most people aren't AWARE of these axioms. They become pre agreed upon axioms because most mature debaters understand that axioms are a point of agreement not only because they seem to be common sense, but because arguing them actually causes the arguments to go BACKWARDS in progression. In essence, there's no use in arguing them, so we move on.



So? This seems to be a consistent problem that people need to AGREE on premises in order for a logical argument to be valid and sound. That's...not true at all. Logic isn't a popularity contest where the ones everyone agrees on are the right ones. That's...not how Logic works at all. In fact, that's a common logical fallacy called the Argument from Popular Authority. If even only ONE person believes a valid and sound argument, and everyone else is being illogical, he/she is not wrong, everyone else is.



Premise 1. Logic covers absolute transcendental facts of the universe. Including A=A and does not equal =/= A.
Premise 2. Using these inarguable observations, one can make accurate conclusions about the reality they live in.
Conclusion: Logical observations are an accurate way to approach understanding reality.



...You can't think of an unassailable proof that you exist? You ARE aware this was settled like...centuries ago, right? Renee Descartes - I think, therefore I am." And the fact that I can DOUBT that I am, means I must NECESSARILY exist.



You haven't shown a single reason why it's GOOD to be illogical, or even that being illogical is useful.

One should follow one's own advice.

Unless on is wrong on their advice.

Btw, if that's referenced at anyone in particular, it's more useful to quote what they're saying in order to actually be witty ;)

Not everything can be solved by logic alone.

Of course not. In order for logical premises to be demonstrated as being true, one needs to have some working knowledge of what they're talking about. That's where science and empirical evidence come into play.

...but without logic and the ability to draw conclusions is gone. Your hit/miss ratio will be rather abysmal and take on a Gaussian distribution. "Thankfully" modern life rarely required serious thought, so the sheeple are usually spared from the consequences of their condition.

Goddamn Flaser, you're a lot harsher than me XD

I'm at least willing to give him that logic alone isn't the way to solve everything. Though I agree with you logic is extremely important and without it, much of our understanding of the universe goes out the window, but part of our ability to implement logical reasoning is OTHER methods which logic can be used on, like mathematics and science.

Basically: Logic is fixed.

Do I win?

And if so, then logic defies "morality" and employs results.

You're the self-proclaimed smart one here, figure it out.

So you're saying that you're wrong about your advice.

Way to fail.

Please point out where I said that.

Oh wait, you can't? Way to fail.

Nope. Logic "enhances" morality, for morality can't ignore truth. Go to 9m25s or 10m22s. (FAKKU doesn't allow time-stamps with You-Tube videos).



Logic on its own can't provide morals. You need knowledge and empathy... however to have workable morals you need logic, otherwise your conclusions will have no connection to reality.



No true Bayesian conspirator will ever claim to be infallible. The statements of a a Bayesian conspirator hinge on knowledge, if the knowledge was partial or wrong then so was the statement.

...however a conspirator can, in good faith, claim to be "Less Wrong" then those who ignore logic.



Read more here:
http://lesswrong.com/

You cannot be this dumb, you seriously cannot be this dumb.

No wait, you are. You really are.

I totally agree with the common sense and logic topic.....


common sense is really something like " If your friends jump off a cliff would you run after them?" the answer would be no since it means death and your "Instincts" tells you that....

I hope I made a good reply here since I am not educated on a college level...

In other words...no, you can't show where I said that, and instead result to just insulting me.

And you think I fail. If I do indeed fail, I've got nothing on your pile of fail.