# Logical fallacies

144 posts / 0 new

Logic is not counterintuitive, people simply give poor explanations. The sense in which an "if p then q" statement is true, if both p and q are true, is not the same sense in which it is true, if both p and q are false.

My primary issue with Nyar's example is that it seems to go against what a conditional statement is supposed to be. For one, there has to be some relationship between the antecedent and the consequent, some presumed correlation, some causal link, anything. There is no relationship between 5 = 5 and 7 = 7, not in practice, not in theory. It is not at all like saying if I go to your office, then I can get the candy.

An antecedent or consequent that can't possibly be true, creates a nonsense conditional

Breezy - My primary issue with Nyar's example is that it seems to go against what a conditional statement is supposed to be. For one, there has to be some relationship between the antecedent and the consequent, some presumed correlation, some causal link, anything.

There is no such requirement in the fields of logic, mathematics, computer science, etc.
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Breezy - An antecedent that can't possibly be true, creates a nonsense conditional

No, it forms a tautology. You can verify that on the 7th and 8th row, 6th column (from the link in this post).

A relationship is required by definition, otherwise there is no condition, and nothing to test. That's why your example is bad. You can test the relationship between going to the office and getting a candy. There is nothing to test when it comes to 5 = 6, it's false by definition, and to suggest that it be a condition for 7 = 8 is nonsense.

Put it this way, the reason why an if p then q statement is true, even if p is false, is because p being false doesn't invalidate the statement. In other words, it's not that the statement is true in reality, it's that you haven't shown it to be false.

That falls apart with something like 5 = 6. It's not only false, it can never be true.

I really think you need to concatenate that with “IMO”...Not to do so suggests that you claim Nyar got it wrong and you have it right.

This is, of course, unless you actually think you know more about mathematics and logic than a mathematician.

No thank you. He should have no problem showing his example is a valid conditional. Perhaps a reference, or a citation of a mathematician using such a conditional un-ironically?

He already called the use of an impossible antecedent to be a tautalogy. Demonstrating that it is not comparable to his office example.

Breezy - Perhaps a reference, or a citation of a mathematician using such a conditional un-ironically?

University of South Africa - As for row four, which involves the falsity of both antecedent and consequent, consider a statement such as "If 1 = 2 then 3 = 4". This statement deserves to be regarded as true, because if we assume that 1 = 2, then we can prove that 3 = 4:

onemathematicalcat - For example, the sentence "If 1 = 2 , then 3 = 4" is vacuously true

Discrete Mathematics and Its Applications 7th ed. Chapter 1.1 - The conditional statement, if 1 + 1 = 3, then unicorns exists -- is true.

If 1 + 1 = 3, then 2 + 3 = 4

University of Maine - From a logical point of view the sentence If 1 + 1 = 3, then pigs can fly is a legitimate implication, although there is no relationship between the component parts.

Introduction to Logic, Waner and Costenoble - "If 1 = 0, then 1 = 1." [listed as true]

Arizona State University - If 1 + 1 = 3, then unicorns exist[listed as true]

University of Nebraska - If 1+1=3, then 2+2=5[listed as true]

Minnesota State University - If 3 < 2, then 9 < 4.[listed as true]

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As I've said before, this isn't my idea. I learned it at university, just like everyone else who studied the subject.

I like how the second reference calls it vicariously true

However, the South Africa reference shows the problem I'm trying to point out. They said "if we assume that 1 = 2, then we can prove that 3 = 4"

Thats a nonsense statement. We can't assume that 1 = 2, by definition. We also can't assume that a square circle exists, it is inherently contradictory. Such an assumption is irrational and impossible. In contrast, we can assume that unicorns exist, we can give it that possibility, even if they do not exist, because it is not inherently contradictory.

The word "if" implies possibility, if there is no possibility, there is no "if"

Well he thinks he knows more about evolution than the best scientific minds the scientific world has, that he has valid objections to what they consider scientific facts. Is it really a surprise he'd think the strict principles of formal logic are wrong when they show religious apologetics to be contain fallacies, preferring to think common logical fallacies are not really valid at all?

I think its ironic that atheists continually appeal to authority rather than thinking for themselves. What isn't surprising though, is your lack of comprehension for the issue at hand, and the issues I've raised on evolution.

I think it's far more ironic that someone who blindly follows an archaic bronze age superstition is accusing anyone of not thinking for themselves. Or that you think you have genuine objections to scientific facts, but only when they refute your religious beliefs, and don't see the bias in that idiocy. As I said if you can genuinely believe you know better than the entire scientific world about evolution, based on nothing but your faith in a bronze age creation myth, then it's hardly surprising you also want to deny the principles of logic because they highlight the fallacious nature of religious apologetics.

Do let us know when the 'issues' you have raised on evolution are peer reviewed in a worthy scientific journal.I'm sure this will happen soon, and you can claim the Templeton prize of million dollars, and your Nobel prize. Thinking for yourself is fine, I'd recommend you start as soon as possible instead of filtering everything through an archaic religion, or believing you know better than the entire scientific world, which is simply delusional.

In the meantime you might want to grasp that not all appeals to authority are fallacious.

"In the meantime you might want to grasp that not all appeals to authority are fallacious."

I'm glad you recognize your statement for what it is, even if you think it merits some sort of exception.

And no; I haven't denied any principles of logic, which again shows that, much like my evolution arguments, you failed to comprehend my points.

Your 'points' on evolution are at odds with the entire scientific world, I don't know whether you're ignoring this salient fact out of duplicity or ignorance of what it means, but it hardly matters. It's clear you can't see them for the risible nonsense they are.The fact you believe denial of scientific facts, and rejection of logic when it refutes fallacious religious apologetics in favour of archaic creation myths is 'thinking for yourself' speaks for itself, Or that you erroneously claimed that accepting the best evidenced scientific facts science has by aligning what I accept as true with the entire scientific world is a fallacious appeal to authority, and can't see the hilarity of that nonsensical claim alongside your adherence to an ancient unevidenced superstition.

How may scientific facts do deny or question the validity of that don't in any way contradict your religious beliefs?

Name 3 for us, you never seem to get around to answering this question.

Do you think common logical fallacies are valid when you think they support arguments for your beliefs? I'm guessing if science evidenced your beliefs you'd be shouting it very loudly as other apologists do. Your section bias is all too evident.

Its always been interesting to me the way you repeat yourself; repeating the same noun and adjective phrases, the same sentence structures, the same line of thoughts, all seemingly as if it were the first time you ever said it.

Can't say I've come across it before.

Sadly I've met plenty of theists and religious apologist who relentlessly refuse to answer questions with any integrity. Instead of using ad hominem fallacy to obfuscate John, try addressing what I've written for once. Your vapid claims get the same answer each time you use them, if you want something new, then offer something new or tangible in defence of your archaic unevidenced beliefs.

Now here's the question again since you ignored it again. How may scientific facts do deny or question the validity of that don't in any way contradict your religious beliefs?

Name 3 for us, you never seem to get around to answering this question.

I really don't care if you find it repetitious, as it doesn't need an answer for others to see your evasion is proving a very salient point about the way you dishonestly cherry pick scientific facts you will accept based on whether they refute your religious beliefs.

How about this. The beauty of language is it's ability to formulate an infinite array of phrases from a handful of rules. We literally have the ability to speak things nobody has spoken before.

Write an original sentence that I have not heard you use before, and I'll answer a single question of your choosing.

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Do you ever read what you have written and think wow, I really am an arrogant cock?

I think that's original.
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Q You think you have bested the entire scientific world in raising scientific objections to the fact of species evolution, that they all seem to have missed in over 150 years of scientific scrutiny, so why have you not published them and got them peer reviewed and falsified evolution?

That was good, I'm impressed.

The answer to your question is time. Last semester was when I was taught how to write scientific papers and how to submit them. I just got accepted into a graduate program in cognitive sciences. I've been communicating with the director, tomorrow I have a meeting with him, in which he'll help me start working on research assignments with professors.

So you will most definitely see my name listed as an assistant on a paper any time soon. Beyond that keep in mind I have my own professional objectives, my own research goals, things that interest me far more than evolution.

But I'm not against submitting a paper on evolution listing my objections. The literature is already full of many that do, and I'm not sure anyone has used my particular approach. So my answer is time. Stay alive, take care of your health, exercise, because submitting a paper and doing the research to back it up, is definitely within my skill set. Keep in mind I'm still young in this professional, and have no intention to rush.

@ J6

Sounds like your professors have found a way to keep you out of harms (well, at least harming patients) way for a while. Hopefully they will teach you some other real skills before you are released to wreak havoc with your eccentric and arrogant beliefs.

@John Re: "Write an original sentence that I have not heard you use before, and I'll answer a single question of your choosing."

*hand raised high above head while standing on top of desk* Oo oo oo!!! Me me me! Pick me, pick me!

Original sentence: Friendly furry Ferbies frolic from fragrant fields, for frisky fanciful fairies frequently fly flittingly forsaking flavored Floam.

Question: How many licks does it take to get to the center of a Tootsie Roll Tootsie Pop?

Given that no two tootsie pops are identical, and neither is the friction nor wetness of each lick, the answer is inconclusive.

@John Re: Tootsie Pop problem

Dammit.... That is actually the best answer I have ever heard to that. Obviously Mr. Owl lied to me when I was a child all those years ago. Thanks. *Big Smile*

Paradoxically one claim for a virgin birth produces a level of certainty thousands of years after the fact that is quite baffling.

I guess tootsie rolls are far less predictable phenomena than virgin births?

@ Nyar
Even I get that now...thank you very much!

John 61X Breezy,

I think it's only fair to say that the error type called "ad hominem argument" was intended for those situations where the attack to the man was irrelevant to the argument at hand. If we had to cross every "T" and dot every "i" it would become very difficult to develop handy, useful guidelines. Such guidelines would more resemble the stuff that lawyers put out. It is an excellent rule if you don't stretch it beyond what it was intended for!

We identify those rules because they are essential to good reasoning. Such rules make it easy to point out certified errors by your opponent and to avoid them yourself. We think they are right because violating them leads to clear errors in reasoning. Much of it is a simple exercise in mathematics, and the rest admonishes you not to put your money on a bad horse. Good reasoning in the world of atoms and energy is all about maximizing your chances of being right.

"I think it's only fair to say that the error type called "ad hominem argument" was intended for those situations where the attack to the man was irrelevant to the argument at hand. "

Not sure if I've responded to this, but it's exactly right. There is a difference between an ad hominem attack and an ad hominem fallacy, and the difference isn't always immediately clear.

It's usually necessary to view the ad hominem in a wider context of what has been said before in the discussion when this happens. For instance Walter has proved himself to be a troll on here unequivocally, but if someone calls him a troll without evidence or arguments it could be justifiably called an ad hominem fallacy, even though no objective reader could disagree with the claim if they read all his posts.

The majority, if not all, of the fallacies boil down to one simple error: the conclusion doesn't follow from the premises. The reason why they occur, isn't because people are illogical, but because we wrongly apply certain heuristics to the wrong situation.

The A-peal to apples - "Take this and put it where the sun don't shine."

@Jared Alesi

Your impressions of Psychology as a soft science are spot on. It is a soft science that relies heavily on patterns of behavior that change over time and statistical probabilities. It has imaginary constructs like motivation, mind, will power, self esteem, consciousness, subconsciousness, repressed emotions, and lots of other garbage. These things are not real. They are simply short cuts in communication that allow people trained in psychology to talk to one another and write reports to insurance companies.

Any psychotherapist who imagines this discipline to have the solidity of a hard science like engineering will engage in techniques like the "Washing Machine Principal." If you put a white shirt in the wash and it comes out discolored, you wash it again. If it is discolored you just keep doing the same thing over and over. (The client is just being resistant. I know I am doing the right thing because that is what the science tells me.) "I know my theory is correct because it has worked before." This is foolishness. There is very little science in the practice of psychology. On top of that, the simple fact of the matter is that 50% of the people who go to therapy get better regardless of what the therapist does. The act of trying to get better actually causes many people to get better.

I am a modern day witch doctor, and not much else. The science can always be manipulated.

People don't seem to realize that if psychology is unreliable, then the whole of science is unreliable. Science is built upon certain naïve assumptions concerning perception, attention, memory, judgment, decision-making, reason, and logic (consider this thread and my comment on development). For centuries, and still today, it is seen as axiomatic that we are capable of reason, and therefore capable of science.

Are you familiar with the history of experimental psychology? It starts off at the Greenwich Observatory. A certain astronomer was interested in the transit time of certain stars. He developed a method of measuring this by overlaying a strand of fiber over the lens, and having his assistant note the time a passing star passed behind it. After some time doing this, the astronomer noticed that his assistants estimate was constantly a whole .75 off from his own estimate. He fired the assistant, and end of story.

That is until another astronomer Friedrich Bessel came along. He noticed that it was not just the assistant that reliably got the measure wrong, but every assistant working on the project was consistently making errors unique to them. Long story short, he developed the personal equation, which each participant would use to correct their unique error. Bessel was the first to use statistics in relation to human behavior.

People during this time, thought nerve impulses were instantaneous; the moment you see or hear something, it is immediately perceived by the mind without delay. Not until psychologists like Helmholtz and Wundt came along, who studied reaction time and nerve impulses, would we understand why these astronomers were producing errors.

There is no science independent of scientists. Which means the observer will always be a variable to his observations. You seem to downplay the use of statistics, but a lone astronomer, with a misguided assumption if how his brain works, is immune to scrutiny. Not until you have many people making the same observation, and use statistical analysis, can you see clearly that the science you thought was objective, was subjective all along.

The delay in human reactions was known at least as early as the time of Galileo (and I have little doubt it was known long before that).

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