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  1. #81
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    This is the same as asking "Which is the correct path to take?"
    And no, it is not the same. You asked for what he was going to say after you asked the question. The truth existed and the liar knows it. But he is supposed to ALWAYS LIE that this tricky and complicated question turns out to be effective and actually simple.

  2. #82
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    Re: What is Logic? (Logic 101)

    It might sound foolish but it's logic that makes it valid. If the Liar brother would point the wrong way, then he said the truth that he was going to lie (on his side because you don't know if he was pointing the wrong or right way).

  3. #83
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    Re: What is Logic? (Logic 101)

    It would appear that you are correct. I misread your question in my haste to get to work. Just shows what happens when you think you can give a quick response around here.

    I'll go back through and read the posts in this thread (haven't read them in a very, very long time) and clean this thread up a bit. The latest discussion seems to be focusing moreso on the riddle than on the topic.
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  4. #84
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    It would appear that you are correct. I misread your question in my haste to get to work. Just shows what happens when you think you can give a quick response around here.

    I'll go back through and read the posts in this thread (haven't read them in a very, very long time) and clean this thread up a bit. The latest discussion seems to be focusing more so on the riddle than on the topic.
    Okay, but the riddle still works good on defining logic. The settings may not be totally applicable to the real world but it shows what logic really is - it is not only the "what", but the "how in accordance to what" in a problem.
    He who is curious both wins and loses.

    -curious boy

    At last, I'm back.

  5. #85
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by curious boy View Post
    Okay, but the riddle still works good on defining logic. The settings may not be totally applicable to the real world but it shows what logic really is - it is not only the "what", but the "how in accordance to what" in a problem.
    Not necessarily. It's a fun riddle, one that causes one to think, but it isn't necessarily the epitome of logic (as in defining it). Using that reasoning, nearly any riddle is sufficient to "define" logic, and that is simply not the case.

    Nor is it the case that a riddle "defines" logic. At most, it is an example of how logic can be used. But even then, it's a stretch to call it a "good example".

    A good example would be to use a syllogism.

    Let's try something...here are a few syllogisms, which is logically valid?

    Syllogism #1
    1. All cats are mammals.
    2. Mammals are warm-blooded.
    3. All cats are warm-blooded.


    Syllogism #2
    1. All cats are mammals.
    2. The natural habitat of a dolphin is the ocean.
    3. Therefore, dolphins are mammals.


    Syllogism #3
    1. All cats are mammals.
    2. Mammals live in California.
    3. Therefore, all cats live in California.
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  6. #86
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    Not necessarily. It's a fun riddle, one that causes one to think, but it isn't necessarily the epitome of logic (as in defining it). Using that reasoning, nearly any riddle is sufficient to "define" logic, and that is simply not the case.

    Nor is it the case that a riddle "defines" logic. At most, it is an example of how logic can be used. But even then, it's a stretch to call it a "good example".
    hmmm... what is not necessary? I'm not saying it's all the synopsis of logic. Defining it, though not totally, is answering the question, "What is logic?"

    I am not really referring to the riddle. What I meant is that the posts which discusses about the riddle, works good on defining it. It is why I said:
    it is not only the "what", but the "how in accordance to what"
    I am talking about correct inferences which is the point of the riddle.

    Quote Originally Posted by Apokalupsis View Post
    A good example would be to use a syllogism.

    Let's try something...here are a few syllogisms, which is logically valid?

    Syllogism #1
    1. All cats are mammals.
    2. Mammals are warm-blooded.
    3. All cats are warm-blooded.


    Syllogism #2
    1. All cats are mammals.
    2. The natural habitat of a dolphin is the ocean.
    3. Therefore, dolphins are mammals.


    Syllogism #3
    1. All cats are mammals.
    2. Mammals live in California.
    3. Therefore, all cats live in California.
    It is #1.
    He who is curious both wins and loses.

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  7. #87
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by curious boy View Post
    hmmm... what is not necessary? I'm not saying it's all the synopsis of logic. Defining it, though not totally, is answering the question, "What is logic?"

    I am not really referring to the riddle. What I meant is that the posts which discusses about the riddle, works good on defining it. It is why I said:
    What you are saying now...is not what you said in the post I responded to. You specifically referred to the riddle itself.

    Quote Originally Posted by Cb
    Okay, but the riddle still works good on defining logic.
    And as to...

    I am talking about correct inferences which is the point of the riddle.
    How exactly are inferences the point of the riddle?

    It is #1.
    No. It's #1 & #3. And this is precisely why syllogistic expression is a far better example of the employment of logic, than fun little riddles.

    Do you understand why this is the case? Do you see why #3 is logically valid?
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  8. #88
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    What you are saying now...is not what you said in the post I responded to. You specifically referred to the riddle itself.
    No, not specifically. I even described the way I referred to the riddle. I did not say, "The riddle defines logic". I said, "The riddle works good on defining logic". It is according to the discussion.

    Quote Originally Posted by Apokalupsis View Post
    How exactly are inferences the point of the riddle?
    Because there is a given, a setting.


    Quote Originally Posted by Apokalupsis View Post
    No. It's #1 & #3. And this is precisely why syllogistic expression is a far better example of the employment of logic, than fun little riddles.

    Do you understand why this is the case? Do you see why #3 is logically valid?
    Sorry, I did not read #3. I thought there would only be one so I settled for #1.

    Yes, I see why #3 is logically valid.


    Apo, syllogism is actually applied in the riddle.
    He who is curious both wins and loses.

    -curious boy

    At last, I'm back.

  9. #89
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by curious boy View Post
    No, not specifically. I even described the way I referred to the riddle. I did not say, "The riddle defines logic". I said, "The riddle works good on defining logic". It is according to the discussion.
    Very well, how does the riddle "work good" (whatever that means) on defining logic?

    Because there is a given, a setting.
    That's not what a logical inference is. I appreciate the discussion in logic, but I'm starting to think that you are new to logic theory by some of your answers. Am I wrong here?

    Hint: I explained what a logical inference is in the op for those who are unfamiliar.

    Apo, syllogism is actually applied in the riddle.
    First off, that doesn't make any sense. You don't "apply syllogism". It isn't a verb. This is another example that makes me suspect you may be new at this, and that's ok, but I'd prefer a much more honest discussion instead of the debater insisting on things that he/she may not have a firm handle on quite yet. It's ok for someone to say they are unsure what "x" is. It's not really ok to "wing it" to save face, and insist X is something that it simply is not. Remember this is a learning tool. It's moving from a false belief to a true belief. That's far more important and productive than being concerned about admitting that one does not know "everything".

    Assuming it was poor grammatical structure (like the "riddle defining logic" bit)...what is the syllogism? What type of syllogism is it? Please define the propositions (AEIO). Which premise is affirmative (major or minor) and what is it specifically? Where is the predicate? What is the middle term? How many times do you distribute it and in which propositions do you do so? Any quantifiers?

    If you genuinely know what a syllogism is, and you genuinely see it, you'll have absolutely no problem answering the above queries that are asked of any 1st year intro to logic student would be more than familiar with. Takes all of 30-60 secs (assuming you are familiar with logic and simple syllogisms).

    Having studied formal, informal, predicate, propositional and a few other symbolic models, I see absolutely no syllogism whatsoever in that riddle. Not every piece of text can be put into syllogistic format you know.
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  10. #90
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    First of all, man discovered logic, not created it. We merely put into words that which we discovered. The way to prove this to your friend is through the use of "first principles" (laws of logic).

    Namely, the law of non-contradiction, law of excluded middle, and law of identity. Nearly all truths can be reduced to first principles. Have her "deny" the following (she won't be able to):

    Law of non-contradiction (or sometimes referred to as "law of contradiction" depending upon your prof)

    A cannot be both A and non-A at the same time in the same sense. Or, A is not non-A. Basically, no proposition can be both true and false at the same time.

    I cannot be both alive and dead at the same time in the same sense.


    Law of Excluded Middle

    A must be either A or not A; or either A or non-A.

    I must be either a human or not a human.


    Law of Identity

    A is A.

    A human is a human (not a cow).

    Use these examples or provide your own using these first principles of logic. These may seem quite simple and obvious...but you'd be surprised how often we miss them in more complex arguments (which is why it is good to try to slow down in a debate, and reduce the argument to its first principle when possible).
    This is formal logic but there are other kinds, better ones I reckon. Formal logic sees cause and effect for example as opposites, but for Marxists this isn not the case, and cause and effect can merge into each other. If you compare formal logic to dialectics its like comparing a photograph with a film. A photograph has its uses, but it is a simplification of real life. Sometimes its useful to simplify, but other time you need to look at the full picture. Real life contains contradictions everywhere and is constantly changing. Everything is interconnected. Quantitative changes can lead to qualitative changes. Life is complex.

    ---------- Post added at 11:26 PM ---------- Previous post was at 11:15 PM ----------

    Quote Originally Posted by Apokalupsis View Post
    Because all first principles are undeniable logically. One can certainly be illogical and deny them...but then, there's the problem of being illlogical.

    I challenge anyone to refute a first principle. It simple cannot be done.
    Ok, lets take reducing interest rates in a recession to stimulate the economy. They are supposed to get rid of a recession. But they lead to frenzied borrowing which then creates bubbles which leads to the next recession. So they are both the cure and the cause of recessions.

    Even A is not equal to A. If you look at those two letters I just typed under a powerful microscope, if it was typed on paper, you would find microscopic differences. A mountain is a mountain but it is different from one year to the next, one minute, one second.

    Ok, you did say in the same sense, and you are applying it to debate. Im just saying formal logic is not the end of it.

  11. #91
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by manc View Post
    This is formal logic but there are other kinds, better ones I reckon.
    There are a variety of modes or types of logic...but each has their uses. The above is Aristotlean Logic. And the basic laws of logic are the same for all logic. You cannot make a statement without using logic.

    Formal logic sees cause and effect for example as opposites,
    No it doesn't. It's merely the language used to convey result.

    but for Marxists this isn not the case, and cause and effect can merge into each other. If you compare formal logic to dialectics its like comparing a photograph with a film. A photograph has its uses, but it is a simplification of real life. Sometimes its useful to simplify, but other time you need to look at the full picture. Real life contains contradictions everywhere and is constantly changing. Everything is interconnected. Quantitative changes can lead to qualitative changes. Life is complex.
    Let me illustrate.

    Take your statement "Life is complex". Should I understand that as being "Life is simple"? Should I read it as "Cows are blue"? Or should I understand the statement to mean "Life is complex"?

    Secondly, are you saying that it is true that life is complex? Or are you saying it is false that life is complex?

    Ok, lets take reducing interest rates in a recession to stimulate the economy. They are supposed to get rid of a recession. But they lead to frenzied borrowing which then creates bubbles which leads to the next recession. So they are both the cure and the cause of recessions.

    Even A is not equal to A. If you look at those two letters I just typed under a powerful microscope, if it was typed on paper, you would find microscopic differences. A mountain is a mountain but it is different from one year to the next, one minute, one second.

    Ok, you did say in the same sense, and you are applying it to debate. Im just saying formal logic is not the end of it.
    You'd have to show how the bold is not applicable to the paragraph above.

    And it is not the case that A = any object. It is the case that A = a term in a logical statement. No one challenges that a mountain changes over time. This is not a matter of logic but of the physical world, science, geology, wind erosion, etc...

    Logic doesn't tell you about the physical world, it tells you how to properly reason.

    You are misapplying or misunderstanding the nature of logic. Your statement about the mountains is as follows:
    Mountain X in the future will not have the same composition as Mountain X does right now.
    You have confused Mountain X to be "A"...it isn't. The actual terms of the logical statement are:

    Mountain X in the future & Mountain X as of right now

    The law of identify (A = A) says:

    Mountain X in the future is Mountain X in the future

    or

    Mountain X as of right now
    is Mountain X as of right now.

    That is the first principle of identity. Something is, what it is.

    If you agree that Mountain X as of right now is Mountain X as of right now (and not a cat for example), then congratulations! You are using proper logic.
    Last edited by Apokalupsis; September 18th, 2010 at 12:50 PM.
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  12. #92
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    If you agree that Mountain X as of right now is Mountain X as of right now (and not a cat for example), then congratulations! You are using proper logic.
    Yeah, but the mountain X as of right now is only equal to itself for an infinitesimally short period of time, and so has no real meaning.

    ---------- Post added at 04:06 AM ---------- Previous post was at 03:39 AM ----------

    Quote Originally Posted by Apokalupsis View Post
    There are a variety of modes or types of logic...but each has their uses. The above is Aristotlean Logic. And the basic laws of logic are the same for all logic. You cannot make a statement without using logic.

    Formal logic sees cause and effect for example as opposites,
    No it doesn't. It's merely the language used to convey result.
    Aristotle wrote "All causes are beginnings". He was a dialectician however, he did understand that cause and effect can turn into each other. Dialectics was very big among the ancient Greeks. Marx called him the "greatest thinker of antiquity". He wavered between idealism and materialism, according to the Marxists Encyclopaedia. He talked about four prime causes. Hegel said Aristotle was "one of the richest and deepest of all the scientific geniuses that have as yet appeared a man whose like no later age has ever yet produced. " Hegel, by the way, was an idealist dialectician. Marx took Hegels work on dialectics, and blend it with materialism, to come up with dialectical materialism.

    Marxism doesnt focus on whether A=A, but on the PROCESS A is a part of. A is never A because it is constantly changing. Dialectics is the study of motion. In real life it may be a process where A become 'not A'. A mountain and a mountain worn down completely by erosion are still connected. A worn down mountain is a worn down mountain, and a mountain is a mountain that will inevitably become a worn down mountain.

    Hegel on Aristotle:
    http://www.marxists.org/reference/ar...paristotle.htm

    Hegel:
    "Consequently, effect contains nothing whatever that cause does not contain. Conversely, cause contains nothing which is not in its effect. Cause is cause only in so far as it produces an effect, and cause is nothing but this determination, to have an effect, and effect is nothing but this, to have a cause. Cause as such implies its effect, and effect implies cause; in so far as cause has not yet acted, or if it has ceased to act, then it is not cause, and effect in so far as its cause has vanished, is no longer effect but an indifferent actuality."

    The dialectical relationship between cause and effect.

  13. #93
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by manc View Post
    Yeah, but the mountain X as of right now is only equal to itself for an infinitesimally short period of time, and so has no real meaning
    Irrelevant to the nature of logic. Logic pertains to terms of a statement. You misused the terms. You have 2 terms: A and B. They are 2 entirely different things manc.

    Aristotle wrote "All causes are beginnings". He was a dialectician however, he did understand that cause and effect can turn into each other. Dialectics was very big among the ancient Greeks. Marx called him the "greatest thinker of antiquity". He wavered between idealism and materialism, according to the Marxists Encyclopaedia. He talked about four prime causes. Hegel said Aristotle was "one of the richest and deepest of all the scientific geniuses that have as yet appeared a man whose like no later age has ever yet produced. " Hegel, by the way, was an idealist dialectician. Marx took Hegels work on dialectics, and blend it with materialism, to come up with dialectical materialism.

    Marxism doesnt focus on whether A=A, but on the PROCESS A is a part of. A is never A because it is constantly changing. Dialectics is the study of motion. In real life it may be a process where A become 'not A'. A mountain and a mountain worn down completely by erosion are still connected. A worn down mountain is a worn down mountain, and a mountain is a mountain that will inevitably become a worn down mountain.
    Irrelevant to the nature of logic.

    I've already given you a few examples to answer...why not work on those?
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  14. #94
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    Irrelevant to the nature of logic. Logic pertains to terms of a statement. You misused the terms. You have 2 terms: A and B. They are 2 entirely different things manc.


    Irrelevant to the nature of logic.

    I've already given you a few examples to answer...why not work on those?
    Well you are the one who brought mountains into it.

    As for Hegel being irrelevant, well he wrote The Science of Logic. This was a major, influential work in the field.

    What examples? That life is complex? Of course it is, thats the whole point. It is more complex than any knowledge or logic. Dialectics is a way to get closer to the reality than formal logic.

    "Logic doesn't tell you about the physical world, it tells you how to properly reason."

    and reason can be separated from the real world? For what purpose? How can logic be valid if it has nothing to do with the real world?

    "You'd have to show how the bold is not applicable to the paragraph above. "

    Dont know what you mean by that. What paragraph? My own?

    "Take your statement "Life is complex". Should I understand that as being "Life is simple"? Should I read it as "Cows are blue"? Or should I understand the statement to mean "Life is complex"?

    Secondly, are you saying that it is true that life is complex? Or are you saying it is false that life is complex?"

    I have no idea why you are asking these weird questions.

    Can you spell it out a bit clearer?

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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    Basically, no proposition can be both true and false at the same time.
    Consider,
    "This statement is not true."

    Paradoxes are examples of this.

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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by manc View Post
    Well you are the one who brought mountains into it.
    You misunderstand. Mountain X is a term in a logical statement. You are misapplying logic. It is incorrectly identifying what the terms are in a statement.

    As for Hegel being irrelevant, well he wrote The Science of Logic. This was a major, influential work in the field.
    I didn't say he was irrelevant. I said your response is irrelevant to what is being said in that it doesn't change what has been said.
    What examples? That life is complex? Of course it is, thats the whole point. It is more complex than any knowledge or logic. Dialectics is a way to get closer to the reality than formal logic.

    "Logic doesn't tell you about the physical world, it tells you how to properly reason."

    and reason can be separated from the real world? For what purpose? How can logic be valid if it has nothing to do with the real world?

    "You'd have to show how the bold is not applicable to the paragraph above. "

    Dont know what you mean by that. What paragraph? My own?

    "Take your statement "Life is complex". Should I understand that as being "Life is simple"? Should I read it as "Cows are blue"? Or should I understand the statement to mean "Life is complex"?

    Secondly, are you saying that it is true that life is complex? Or are you saying it is false that life is complex?"

    I have no idea why you are asking these weird questions.

    Can you spell it out a bit clearer?
    No...you are misapplying logic to terms in a logically structured statement.

    Let's start with something very simple. I think after doing this you'll know exactly what I'm referring to and what is meant by first principles and how they apply.

    Can you please identify the terms of each of the following statements (there are 2 in each):
    1. All cats are mammals.
    2. Karl Marx is a human being.
    3. Marx is Japanese.
    4. Apok is a donkey.


    ---------- Post added at 01:12 PM ---------- Previous post was at 12:46 PM ----------

    Quote Originally Posted by verrsili View Post
    Consider,
    "This statement is not true."

    Paradoxes are examples of this.
    This is commonly referred to as "Liar's Paradox" (or formally as The Epimenides Paradox). It's truth value is neither true nor false since it violates the principle of bivalance.

    It is not a logically valid proposition in the sense that one cannot derive a truth value from it. A proposition is a declarative sentence that is either true or false. It's a logical sentence whose truth value can be evaluated with respect to some context.

    A paradox is a statement which contradicts itself. It is not the same as a logical proposition.

    If we were to use the term "proposition" to mean any statement in an argument, I would agree (that is, use the term loosely and synonymously with the term "statement" or even "sentence", but it really would not hold much meaning IMO as we should be able to properly further define the statement in question. Thus, I believe is is proper to use the more formal understanding of the term (for the purposes of distinguishing the types of statements available).
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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    [/COLOR]
    This is commonly referred to as "Liar's Paradox" (or formally as The Epimenides Paradox). It's truth value is neither true nor false since it violates the principle of bivalance.

    It is not a logically valid proposition in the sense that one cannot derive a truth value from it. A proposition is a declarative sentence that is either true or false. It's a logical sentence whose truth value can be evaluated with respect to some context.

    A paradox is a statement which contradicts itself. It is not the same as a logical proposition.

    If we were to use the term "proposition" to mean any statement in an argument, I would agree (that is, use the term loosely and synonymously with the term "statement" or even "sentence", but it really would not hold much meaning IMO as we should be able to properly further define the statement in question. Thus, I believe is is proper to use the more formal understanding of the term (for the purposes of distinguishing the types of statements available).
    Well there are other examples of paradoxes I could bring up, such as the Sorites paradox which is not a simple "statement which contradicts itself." Situations such as Backwards Induction are also not STATEMENTS which contradict themselves. Consider the following example:

    Clare is non too pleased when, a week before her 18th birthday, her parents, who are scrupulously reliable, announce that they are throwing a surprise birthday party for her. Clare is at first horrified, but then she starts to think about precisely what her parents have promised, and realizes that she has nothing to worry about. The party is not going to take place.
    Her reasoning is that as her parents stated that the party would happen on a weekday the following week, and that it would come as a surprise, then it cannot happen on the Friday, because if it hasn't happened by midnight on Thursday, she will know it has to happen on Friday, which means that it won't be a surprise. But it follows then that it also cannot happen on Thursday, since if it hasn't happened by midnight on Wednesday, she will know that it has to happen on Thursday (since it can't happen on Friday), which again means that it won't be a surprise. This reasoning works for all the days backwards through the week, which leads Clare to conclude that the party cannot take place.

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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by verrsili View Post
    Well there are other examples of paradoxes I could bring up, such as the Sorites paradox which is not a simple "statement which contradicts itself." Situations such as Backwards Induction are also not STATEMENTS which contradict themselves. Consider the following example:

    Clare is non too pleased when, a week before her 18th birthday, her parents, who are scrupulously reliable, announce that they are throwing a surprise birthday party for her. Clare is at first horrified, but then she starts to think about precisely what her parents have promised, and realizes that she has nothing to worry about. The party is not going to take place.
    Her reasoning is that as her parents stated that the party would happen on a weekday the following week, and that it would come as a surprise, then it cannot happen on the Friday, because if it hasn't happened by midnight on Thursday, she will know it has to happen on Friday, which means that it won't be a surprise. But it follows then that it also cannot happen on Thursday, since if it hasn't happened by midnight on Wednesday, she will know that it has to happen on Thursday (since it can't happen on Friday), which again means that it won't be a surprise. This reasoning works for all the days backwards through the week, which leads Clare to conclude that the party cannot take place.
    Interesting "paradox" (quotes because I don't see how it truly is one...or is not a very strong one*, but that is irrelevant). However no one is denying that there are paradoxes. They are interesting to think about.

    But I don't see the relevancy of them in this thread. I don't know what you are trying to argue here in other words.



    * The reason I say it's a pretty weak "paradox" is because of the context in which the original statement was made. That is, at time X, she does not know when the party will happen. It's like me telling you that I will respond to your next post w/i 24 hours of you posting it. It will be a surprise when I do. All you know is that I will indeed post it in 24 hours after the time that you create your next post in this thread.

    You have no idea when that will be. You can theorize all you like. You can wait on your computer and refresh all you like. But the truth of the matter is, you will indeed be "surprised" (merely see the post unexpectedly at that particular time...since you cannot expect it at any specific time) when it does occur. In order for you not to be surprised...or rather...in order for you to expect when my response will be posted...you have to know right here and now when I will do so. You can't know that, therefore you will indeed be "surprised".

    Logic is a real world system. It is real, that she will have a party and she does not know when it will be. It is reality that I will respond to your post and you do not know when. As an example of a real world application, similar to the scenario you provide above (and found from Wikipedia):

    She reasons that it cannot occur on Friday, since if it had not occurred by the end of Thursday, she would know the execution would be on Friday. Therefore she can eliminate Friday as a possibility. With Friday eliminated, she decides that it cannot occur on Thursday, since if it had not occurred on Wednesday, she would know that it had to be on Thursday. Therefore she can eliminate Thursday. This reasoning proceeds until she has eliminated all possibilities. She concludes that she will not be hanged next week.

    To her surprise, she is hanged on Wednesday.
    The girl will have a birthday party and she does not know when. She was wrong. The girl above, using the same line of thinking as the birthday girl will be hung. She was wrong. Neither knew when they were going to experience the event. Yet, they did. And did so despite attempting to rationalize it away.

    Regardless, I fail to see the relevancy of the submission of such a paradox in this thread (or how it relates to the nature of logic). Paradoxes do not "disprove" logic.
    Last edited by Apokalupsis; September 19th, 2010 at 05:06 PM.
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  19. #99
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    Re: What is Logic? (Logic 101)

    Can you please identify the terms of each of the following statements (there are 2 in each):
    All cats are mammals.
    Karl Marx is a human being.
    Marx is Japanese.
    Apok is a donkey
    well yeah, these are obvious examples, very simple and straightforward.

    But we have endless debates over whether

    Stalinist Russia was socialist - was it or wasn't it? perhaps it was and it wasn't at the same time.

    for example.

    Or as I said,

    low interest rates are a cause of recessions
    low interest rates are a cure for recessions.

    both are true

    I am saying that when discussing real life, Aristotelean logic isn't enough. You have to look at the process, the living movement.

    In a thread I was accused of saying two things that seemed contradictory. I replied that life is contradictory, and went on to explain why the two things I had said could both be true. You have to allow for the complexity of the real world or any debates are worthless. A thing CAN be both good and bad. Low interest rates are both good and bad for a capitalist economy.

    You cant always expect a yes or no answer.

    ---------- Post added at 11:18 PM ---------- Previous post was at 11:05 PM ----------

    Ok you might say low interest rates are good and bad because of different circumstances. But at what POINT does low interest change from being good to bad? This is an example of qualitative change leading to quantitative.

    At what point did Russia cease to be a workers state? Did the mountain cease to be a mountain? A cease to be A.

    ---------- Post added at 11:27 PM ---------- Previous post was at 11:18 PM ----------

    Thing is, when you stop and think about it, you say, Mountain X is equal to itself for a split second in time, but its not a very useful thing is it? It its only relevant for a micro-second. Most people just think of a mountain as being a mountain. Marxists (and geologists) think of it as more a process than a thing equal to itself. Therefore a mountain and a pile of dust it inevitably becomes are simply two aspects of one process.

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    Re: What is Logic? (Logic 101)

    Quote Originally Posted by Apokalupsis View Post
    Let's try something...here are a few syllogisms, which is logically valid?

    Syllogism #1
    1. All cats are mammals.
    2. Mammals are warm-blooded.
    3. All cats are warm-blooded.


    Syllogism #2
    1. All cats are mammals.
    2. The natural habitat of a dolphin is the ocean.
    3. Therefore, dolphins are mammals.


    Syllogism #3
    1. All cats are mammals.
    2. Mammals live in California.
    3. Therefore, all cats live in California.
    Quote Originally Posted by Apokalupsis View Post
    It's #1 & #3. And this is precisely why syllogistic expression is a far better example of the employment of logic, than fun little riddles.

    Do you understand why this is the case? Do you see why #3 is logically valid?
    Putting aside the grammatically misleading and poorly structured question as to which of the posed syllogisms are valid, your claim that #3 is valid is simply wrong.

    Several of your sentences are not in standard categorical form. They must be translated into standard form to be properly evaluated. The second premises in both syllogisms #1 and #3 are not quantified and are therefore ambiguous. Do they refer to all mammals or only some mammals? The natural interpretation is in the first case that all mammals are warm-blooded, but in the second case that only some mammals live in California. There is no justification for insisting that the second premise of S3 (which should really be the first premise since it contains the major term) be interpreted as a universal categorical rather than a particular one. Thus S3 commits the fallacy of undistributed middle and is invalid.

 

 
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