Comments

  • David Hume
    Yep. It implies that induction is invalid.Banno

    Not the answer that I was expecting. But it does justify every single post I wrote in response to your claim. For I was right: you do think that the fact that induction is deductively invalid (i.e. not truth-preserving) means that there is something wrong with it.

    I was expecting you are going to say something along the lines that induction does not adequately represent the manner in which we naturally reason. For reasoning is, as you claim, something that cannot be captured by words, something that forever transcends them. To which I would have responded with something along the lines that every model of reality is grounded in a subset of reality and is therefore always a good candidate for being a simplification of the said reality. So there should be nothing strange when we discover that our models are not perfectly accurate; for in most instances, they were not even expected to be perfect.
  • David Hume
    We had agreed that induction was (deductively) invalid. You didn't see that as an issue.Banno

    What's the relevance of stating the obvious fact that induction is not a deductively valid method?

    What's the relevance of stating that induction is not truth preserving?

    What's the relevance of stating that the following argument . . .

    1. All observed As are Bs
    2. Therefore, all As are Bs

    . . .is such that its premise can be true and its conclusion still be false?

    Noone disagrees with that.
    Noone disagreed with that.

    The subject has been the relevance of making such a statement.
    Does it imply that there is something wrong with induction?
    What does it imply?
    Does it imply anything at all?
  • David Hume
    It's not a method; its not algorithmic. It's just seeing the pattern.Banno

    What you're saying, probably without realizing it, is that pattern recognition is an entirely random process.
  • David Hume
    But for fun, do you believe the tower is 324m tall yourself? Just tell me yes or no! And how.

    And when during the day is it so exactly 324m tall? Are we now talking about the hot Eiffel tower that is 15cm taller in the heat of the midday sun, or the one that is 15cm shorter when night falls and its cools down?

    Do we in fact now have two Eiffel towers. Or a vast ensemble - one for every nanometre of variation.

    Oh goodness, how do we measure the height as it expands/contracts unevenly as the sun hits only one side. It can bend 18cm away from the sun. So which is its true height now - the actual distance to the ground or the full distance if it were standing up straight?

    Of course, Banno the tourist guide doesn't need to care. He just reads his facts off Wiki. But Banno the scientist might want to rely on some more careful process of inquiry. A hand-waving approach always makes for poor philosophy.
    apokrisis

    Apo's having a field day with Banno. Made me giggle.
  • There is no emergence
    Gender to me is similar to state of a system, like gas, liquid, solid in water.bahman

    The state of a system is simply the set of values its variables are assuming. If the system has two variables such as height and gender then its state would be something like "190cm, male" or "170cm, female". Gender need not be a state. The same applies to consciousness.
  • There is no emergence
    Because the state of system is a function of the properties of its parts.bahman

    There is a correlation between height and gender. The taller the person, the more likely the person is a man. And vice versa. That's an example of a very simple system. You have two variables that are related to each other in a specific way. One of the variables is quantitative (height) the other is qualitative (gender.) So how is it possible for a quality such as male/female to arise from quantity?
  • There is no emergence
    I believe that there could be a correlation between different variables depending on state of system. I however don't recall any physical example. Correlation is the result of interaction. It however cannot leads to consciousness.bahman

    The question is: why is it impossible for the brain to be conscious if atoms and molecules are not conscious?
  • Time: The Bergson-Einstein debate
    ↪Magnus Anderson I cannot teach you how to conceptualize a problem. Unfortunately, there is no training for such a skill I'm any educational courses other that art. So you either have to train yourself through hard work or be at the mercy of others to tell you the answers for the rest of your life. I can only suggest that you try to conceptualize the problem in your mind.Rich

    Alright, so you do not want to define what it means for life to be starting and stopping which means the discussion is over and it's your choice. No problem.
  • There is no emergence
    Brain cannot become conscious if atoms and molecules are not conscious.bahman

    So there can be no correlation between variables unless variables are of the same type?
  • Time: The Bergson-Einstein debate
    You are just START/STOP which is the nature of the Paradox and my very first question to you. Do you believe feel like your life is coming stopping and going? This is rhetorical. I don't need an answer.Rich

    You need to define what it means for life to be starting and stopping.
  • Time: The Bergson-Einstein debate
    ↪Magnus Anderson How something can be at rest all the time and moving? Hmm. I'll try it out later today and see if I can teleport myself somehow.Rich

    The arrow is resting AT every instant but it is not resting BETWEEN instants.

    Even the idea that the arrow is resting at every instant is strange. Rest is something that takes place BETWEEN instants.
  • Time: The Bergson-Einstein debate
    Well apparently you are fine with this so nothing is going to convince you otherwise. For me, it is strange and doesn't coincide with every day experience.Rich

    Maybe you should try to explain why you find it counter-intutive?
  • Time: The Bergson-Einstein debate
    If a moment is without duration, exactly how many moments does it take to make one second? The stuff that the clock is measuring. That science it's measuring.Rich

    There can be any number of moments within a second. Bergson claims that time is indivisible. I claim that time is not only divisible but also infinitely divisible.
  • Time: The Bergson-Einstein debate
    If you understand the paradox, then you understand why moments and spatiality yields it.Rich

    I understand the paradox. The paradox is a word game. In other words, there is no paradox. If an object is at rest at every point in time, it does not follow that it is not moving. The solution to the "paradox" is to understand what the word "motion" means.
  • Time: The Bergson-Einstein debate
    Well then you have an expected paradox. It is an outgrowth of your ontology which brings us right back to my first question, if you think you are moments then do you feel each moment starting and stopping.Rich

    You will have to define what it means for a moment to "start and stop". Moments do not start and stop, they simply follow one after another. For a moment to start and stop, it must have a duration. But moments are durationless by definition.
  • Time: The Bergson-Einstein debate
    If the moments are continuous there are no moments. That was Bergson's point. This is what Zeno's paradoxes are all about. When you do away with points (the arrow never stands still) the paradoxes vanish. Whenever there are paradoxes there are problems with the ontology. Moments are the problem. Spacialization of time creates these paradoxes.Rich

    Right. Bergson thought that Zeno's paradox of the arrow demonstrates that time is not made out of points. But I don't agree. Zeno's argument is just a word game. Motion is a difference in position between two points in time. That's what the word means. The fact that we can say the object is at rest at every point in time does not mean its position is not different at different points in time.
  • Time: The Bergson-Einstein debate
    I believe meditation is a technique for focusing ones mind, no? I suppose it could be considered a denial that unfocused use of the mind delivers the truth, or perhaps there is the denial of the ascetic who runs away to live on a mountaintop. There's good and bad denial right. Denial of a lie could be pretty important.Perplexed

    Meditation is a tool that we use to reduce mental stimulation. So yes, by eliminating distracting impulses, it can help us focus. It's a very useful too but in the case of those who consider themselves mystics it is a tool used to simplify their process of thinking to a degree that is quite astonishing.

    Are you sure it is not just the conception of time as only a succession of moments that he is opposed to? As this is a very simplistic and linear way of describing it.Perplexed

    No, he says that such a conception falsifies the reality of time.
  • Time: The Bergson-Einstein debate
    Time is exactly as you are experiencing it. Is time starting and stopping for you as a succession of moments? Mine is continuous.Rich

    What does it mean for time to be "starting and stopping"? The point is that my past is a succession of moments. You have one moment coming after another moment.
  • Time: The Bergson-Einstein debate
    Bergson opposes spacialization of time. If you don't understand what I just said, you have to either think about it or read about it.Rich

    Or you can simply explain it to me so that I can be enlightened.

    "Spatialized time" is precisely the kind of time that I am talking about i.e. the kind that can be thought of as a succession of moments. For Bergson, everything that is divisible is considered "spatial".
  • Time: The Bergson-Einstein debate
    ↪Magnus Anderson What you are describing is not mysticism but denial. i.e. hiding from valid distinctions. The trouble is that a great deal of discrimination takes place without us being aware.Perplexed

    That's right. What I am describing is denial. The thing is that mysticism in general is about denial. That's simply what it is. Why is it that meditation is the holy grail of mysticism? Is it not because meditation is a form of denial? It is a return to a more primitive way of thinking that is known as intuition.

    It seems to me that Bergson takes a phenomenological approach to time so he would be interested in discussing distinctions as they appear rather then by comparative measurements of different observers via the objectification of space-time.Perplexed

    Bergson is opposed to any conception of time as a succession of moments.
  • Time: The Bergson-Einstein debate
    Observation. This guy thinks that time is something other than a sequence of moments. When you ask him what this "something other" is, he tells you that it is something that cannot be described using words.
  • Time: The Bergson-Einstein debate
    I think that Bergson, like every other mystic, is against awareness. He hates it. He wants to go back to being blind because he finds reality to be too painful. Normally, people want to be aware and that means they want to discriminate; they want to see separate and distinct elements where previously only a unity was seen. But when reality becomes too painful, the opposite process becomes fashionable.
  • David Hume
    You are not saying anything relevant.

    I was responding to Banno.

    Here's the first paragraph form the Shorter Rutledge Encyclopedia of Philosophy, inductive inference.

    According to a long tradition, an inductive inference is an inference from a premise of the form "all observed A are B" to a conclusion of the form "All A are B". Such inferences are not deductively valid, that is, even if the premise is true it is possible that the conclusion is false, since unobserved A's may differ from observed ones.

    Now, does anyone here think that this is wrong? Surely at least we have agreement on this.
    Banno

    Basically, the encyclopedia is saying that inductive arguments have the following form:

    1. All observed As are Bs
    2. Therefore, all As are Bs

    You must be smarter than this encyclopedia because it says nothing about the conclusion being "merely" probable. Right?

    I generalized this to:

    1. Some As are Bs
    2. Therefore, all As are Bs

    The premise is no longer restricted to observations.

    Now I have to ask: what exactly is your point?
  • David Hume
    You problem is that you just don't know what you are talking about.
    If you don't find out, people are just going to laugh at you.
    charleton

    Tsk. You're being a fool.
  • David Hume
    Rubbish.
    This is just poor logic. A broken deduction, pretending to be something. Nothing to do with induction at all.


    An inductive argument is more like X happens after Y all the time. So maybe X is caused by Y.
    Post hoc ergo propter hoc is only fallacious if it is wrong.
    charleton

    You're being pedantic. It's what people to do in order to feel superior (when they are actually not.) See Banno for example.

    Here's an amendment to my argument:

    1. Some Ps are Qs (e.g. all of the observed ones)
    2. Therefore, all Ps are Qs (in my opinion, so yeah, maybe I'm wrong, it's not certain)

    Basically, what we have here is people who do not think ob their own but parrot. So when someone comes along and does not repeat the popular narrative word-by-word he's subjected to pathetic pedantry.
  • There is no emergence
    ↪bahman The only experience that I have had that is fully emergent is a new idea or epiphany. This would represent growth of the mind.Rich

    Depending on how you define the concept of emergence, you can say that pretty much any event is emergent. This is to emphasize that the concept of emergence must be clearly defined.

    What is emergent if not that which cannot be predicted by some specific model of reality? Emergence is a relation between an event and a model of reality. There is no emergence outside of this relation. You cannot say that an event is unpredictable on its own, in the sense that it cannot be predicted by any kind of model reality, because it is possible to predict any kind of event through sheer luck. You can predict the entire universe through luck. Instead, what you can say is that an event cannot be predicted by particular model of reality. If your model of reality says that all people are bald then your model of reality cannot predict people who are not bald. That's the same exact way in which ideas can be emergent -- by not being predictable by some particular model of reality.
  • There is no emergence
    "Emergence" is a complicated topic (in part because there is no common view of what it is).SophistiCat

    The word "emergent" simply means "arising unexpectedly". It refers to an observation that contradicts our model of reality. It refers to an observation that is unpredictable in the sense that it cannot be predicted with our model of reality. If your model of reality says that every swan is white then a black swan would be considered emergent because your model cannot predict it. Very simple. Unfortunately, some people are confused and so they want to make everything unnecessarily complicated and that under the guise of profound complexity.
  • David Hume
    Constraint is, as I understand it, simply a limit to what is possible. The opposite of it is freedom.
    — Magnus Anderson

    Yep. Simple really.

    The world we live in, in other words, is stable enough to make induction good at making predictions. This makes perfect sense.
    — Magnus Anderson

    Yep. You got it again.
    apokrisis

    Alright. That might be the case. But I think that you're saying a bit more than that. I am not sure. Your insistence that you're not interested in narrow subjects such as logic, epistemology, conceptual analysis, etc suggests to me that your interest lies in devising a theory of everything i.e. a theory that explains how everything in the universe works. And I belive that's what you mean when you talk about metaphysics. Metaphysics = a theory of how everything works. You also talk about how your metaphysics is not reductionistic but instead holistic. How do we interpret this? I interpret it to mean that you are in fact a monist. A dialectical monist. Yin-yang philosophy. You want to unite the opposites. Uncontrolled interaction is not enough. There must be a central force, some kind of God, controlling the antagonism. Hence your focus on trichotomies, triadic conceptual structures. Very reminiscent of Aristotle's theory of golden mean. You have a center and two extremes. Left, middle and right. So in the case of order~chaos dichotomy, you want to subsume the two to a third category which is basically that of order (which explains why you make a distinction between constraints and patterns or regularities which you say are merely observable.) So you're acknowledging the dualism and then reducing it to monism under the guise of trialism. There is chaos but this chaos is subsumed to order. I think that Perice said something along the lines that there is no absolute certainty but that there is absolute truth. That would make him a very clever absolutist in my book. But is he? I am not sure. Further investigation required.
  • David Hume
    ↪Magnus Anderson

    No I can't comprehend your eccentric account of the rules of reason.
    Janus

    I don't think that's eccentric. I think that what they teach you in school is eccentric. The rules of reasoning, or inference, is a very intuitive idea.

    You know what a mathematical function is, right? It's a relation between two sets where every element from the first set is associated with exactly one element from the second set. Now, I think that this is too strict. Instead of thinking in terms of mathematical functions, I tend to think in terms of partial functions, since these are more relaxed; or better yet, in terms of relations. But even these are kind of strict . . . The basic idea is that you have two sets which may or may not be related to each other. It's sort of like a system except we're not talking about variables, parameters, etc. Well, we can, if you want; we can say we have two variables or two parameters but no more and no less than that. That's what every logical argument fundamentally is. Can we agree on that? We have a set of premises on one side and a set of conclusions on the other side. And we also have connections, or associations, between the two sets (which may also be absent; again, we love general concepts because they give us more freedom.) We need some basic rules to limit what kind of premises and what kind of conclusions are permitted. Once these are set, we need to determine what kind of associations are permitted and/or expected. This is where "the rules of reasoning" kick in. This is what determines whether any given argument is valid or not. No notion of consistency whatsoever. Just associations and rules that determine what kind of associations are legal and what kinds are not. You can't just associate any kind of premise with any kind of conclusion, right? Reasoning is a process that works according to a set of rules. So if you note that "All men are mortal" and that "John is mortal" you cannot conclude that "John is a man". You can't associate these two premises with that conclusion. It's against the rules.
  • David Hume
    ↪Magnus Anderson

    I would have to first understand what you mean (and you haven't explained it in any way that makes it all clear to me) before I could agree or argue against it. So, best leave it, I guess. :s
    Janus

    You don't understand what it means for a logical argument to abide by the rules of reasoning?
  • David Hume
    "Truth-preservation" is really just consistency, which means not having premises which contradict one another or the conclusion. The validity of deductive arguments is independent of the truth of premises, maybe that's where you're becoming confused; I don't know.Janus

    Maybe I'm not the one who's getting confused ;) I understand very well what truth-preservation is. My point is that it's a concept that is 1) narrow, 2) complicated and 3) deceptive. Don't tell me it's not complicated. It is. There is a much simpler and a much better way to define logical validity. Validity in general, outside of logic, means "the state of being legally acceptable". We can define logical validity in the same exact way, as the state of being legally acceptable. This means that a logical argument is one that abides by the rules of reasoning (whatever they are.) This is broad enough to cover all the different types of validity (not only truth-preservation), it is not unnecessarily complicated and it is not deceptive. It fits every single need perfectly. If we need specific concepts, we can use those too, but we don't have to rely on them all the time. They are, in many situations, inappropriate. Again, that's how I define the concept of validity and that's how I think validity should be defined. It's not how most people think. You don't have to accept it if you don't want to though you can argue against it.
  • What is NOTHING?
    I understand the problem. NOTHING, defined as nonexistence, is difficult to grasp. We're in the habit of or are confined to understanding in terms of attributes/properties which, by far, are positive in nature. What I mean is we need some attributes that are attached to a concept or object and only then do we even begin to understand them. However, unlike most objects (mental/physical) NOTHING is defined in the negative. In fact it is the ultimate negative - the absence of everything. In a way we could say "There's NOTHING to understand."TheMadFool

    Negative concepts are defined in relation to one's expectations. The word "nothing" means nothing other than "absence of that which was expected". It must not be taken literally. If I open a box and find "nothing" in it what this means is that what I found in it is not one of those things I was expecting to find. In the same way, non-existence means nothing other than "the kind of existence I was not expecting". That's all it means. I don't think this is difficult to grasp.

    This probably doesn't make sense give what I've said above but I have commented on how math can make sense of NOTHING by equating it to zero.TheMadFool

    Zero means "no number of objects of expected type". I say "there are zero apples in front of me" to mean that whatever I see in front of me (e.g. one computer monitor) is not a number of apples equal to or greater than one.

    I think "nothing", the word, is quite different from other words. Other words have physical/mental referents but "nothing", by definition, lacks any referent.TheMadFool

    "Nothing" refers to that which contradicts our expectations. "There is nothing on the screen" means the screen does not contain what we define to be "something". For example, I might be expecting to see a picture, a video, a text . . . but none of these are present; therefore, nothing is on the screen.
  • About the existence of a thing.
    Any thing can exist only onceDaniel

    This depends on how you define the concept that is represented by the word "thing". If it's too specific, the object will exist for a very short period of time (i.e. once.) If it's too generic, the object will exist for a very long period of time (e.g. forever.) Depending on how you define your words, you can say that everything exists only once or that everything exists for all times.

    which happens when it becomes; after becoming, it cannot be anymore, for it is subject to change, and necessarily "becomes" something else. Before becoming, it certainly is not the thing that it will be. So, it is as if something exists (potentially) up to the point it becomes an actuality; after that, it "becomes" literally nothing, for the memory of it is totally different to the thing itself.Daniel

    Your concept of "thing" goes through three stages: potentiality, actuality and death. Again, this is a matter of definition. It's not an empirical matter.
  • David Hume
    I am going to return to something @apokrisis said in response to me on page 8.

    Constraints generate regular patterns in a probabilistic fashion. So that is how science understands physical systems. And it is how we would speak of nature if we take a systems view where we grant generality a reality as a species of cause.

    So again, it is simply a reflection that I am arguing from a consistent metaphysical basis. It is how reality would be understood if you believe in an Aristotelean four causes analysis of substantial being.
    apokrisis

    I am struggling to understand what you mean when you say "constraint". The way I understand it, and the only way I can sensibly interpret it, is that the word "constraint" means nothing other than pattern, regularity, law, order, etc. However, as it appears, that's not what you mean by the word. Instead, you mean something . . . else. What this else is I don't know. I think it has something to do with "downward causation". Which is another obscure term that is often thrown around. Perhaps I should start a new thread dedicated to this concept? Just to see if someone else can elucidate it for me. Or maybe someone here can help me with it?

    Constraint is, as I understand it, simply a limit to what is possible. The opposite of it is freedom. It is that which allows us to discriminate between those possibilities that are more likely and those that are less likely. It's a very simple concept. But your exposition is generally quite obscure and complicated (as is that of Charles Sanders Peirce.) This suggests to me that we might not be on the same page.

    You say that "history builds constraints on free possibility". The only sensible manner in which I can interpret this statement is in the sense that the world we live in is relatively constant. The universe is flux, i.e. it is constantly changing, but it is doing so at a rate that is sufficiently low to make induction successful in most cases. The world we live in, in other words, is stable enough to make induction good at making predictions. This makes perfect sense. But the fact that you do not express yourself in such simple terms suggests to me that your point is a different one. In fact, it suggests to me that you find this type of process philosophy, the one championed by Heraclitus and Nietzsche, deficient in certain regards.
  • David Hume
    That's not what I think. Just because the premises are true, or can be true, does not mean the argument is valid. "True xor true = true" is not valid even though its premises and conclusion are all logically true and equal to true.
  • David Hume
    Where I disagree with Banno is that it is appropriate to submit inductive reasoning to the criterion of logical validity; which belongs to only to deductive reasoning. I also may disagree with him in thinking that all inductive reasoning can be reframed in deductive form and that it then does become subject to what you would call the "narrow" notion of validity.Janus

    If you define validity the way he does, as truth-preservation, then yes, he's right, induction is invalid because its conclusion can be true and its premises, defined restrictively, false. There is no arguing with this. The question is: why is that relevant? The answer is probably that it isn't relevant. The "problem" with induction is that there is no problem with induction but with deduction. The problem is our understanding of logical necessity. It's a very deceptive concept. We say that a deductive argument is valid if it is impossible for the premises to be true and for the conclusion to be false. This suggests that there is such athing as absolute certainty. And this is caused by the fact that we are confusing two different types of premises: low-level premises (such as observations) and high-level premises (such as general statements.) Put simply, we are confusing observations with assumptions. That's a problem. Induction operates on low-level premises (observations) whereas deduction operates on both low-level premises (observations) and high-level premises (generalizations.) Observations cannot contradict other observations. What observations can do is they can contradict our generalizations or assumptions. This is because generalizations are derived from observations. So if the base of observations from which a generalization is derived changes, it's very possible for the generalization to change as well. Take a look at the following argument:

    1. All men are white
    2. Socrates is a man
    3. Therefore, Socrates is white

    Insofar the second premise is a raw observation it cannot change if the conclusion turns out to be false. However, the first premise can because it is a general statement. Such a general statement is derived inductively from previous observations. It's an open system. If it is possible for the set of observations on which it is based to change, for example by making a new observation, then it is possible for the statement to change as well. If the conclusion turns out to be false then we'll have a new observation in our set of observations and this observation, telling us that there exists a man who is not white, would require that we change our conclusion. On the other hand, exceptions do not disprove the rule, they merely make it weaker. So if a thousand men are white and a single man is black then we can preserve our general statement. But if we reach a point where a thousand men are white and a ten thousand of men are black, then we'd have to change it. This is, of course, a simplification of what's going on in reality. Our conclusions need not be this simplistic in practice. We can let exceptions influence our actions. But describing in words how this process works is a chore.

    Both deductive and inductive arguments are adaptive it's just that deduction adapts through contradiction whereas induction adapts through observation. The second might also be true of deduction but it's usually not the case because most people see deduction as distinctively negative (or eliminative) process. In fact, they think of it so negatively that they think that every contradiction requires a change in one of the premises. Which is sort of true but is also sort of insane. As Einstein said and Popper thought, "No amount of experimentation can ever prove me right; however a single experiment can prove me wrong." The question is, of course, how precise you want to be. Most people are fine with ignoring exceptions. Within that sort of mindset, falsification/negation is not so different from verification/affirmation. Many deductionists also think that deduction can only tell you what's wrong and never what's right. Think of Socrates, think of his dialectic, think of his famous statement "the only thing I know is that I know nothing."
  • David Hume
    OK, I think I see where you are coming from now. It may be consistent with "some Ps are Qs" that all Ps are Qs, but not that no Ps are Qs. So, you are thinking of logical consequence, not in the sense of logical entailment, but of semantic consistency.Janus

    I am not sure we are on the same page. I don't think that the argument is valid because the two sentences are consistent. I don't even know what that means. I am saying that the argument is valid because it does not violate the rules of that particular type of reasoning. In induction, the rule is "if most Ps are Qs then you must conclude that all Ps are Qs." The rule is implicit in the narrow definition of induction making inductive reasoning necessarily valid (i.e. it cannot be invalid.) I covered this in one of my previous posts.

    Here's a general form of probabilistic argument:

    1. X out of Y Ps is Q
    2. Therefore, this P is R

    I intentionally define probabilistic reasoning to be of this general form in order to make it possible for it to be invalid.

    Here's a valid probabilistic argument:

    1. 3 out of 5 men are alcoholics
    2. Therefore, this man is an alcoholic

    Here's an invalid probabilistic argument:

    1. 3 out of 5 men are alcoholics
    2. Therefore, this man is not an alcoholic

    Why is this argument invalid? Because it violates the rules of probabilistic reasoning. The main rule of probabilistic reasoning is that if most Ps are Qs then you must conclude that a particular P is also a Q. If you don't, the argument is invalid.
  • David Hume
    You are focusing too much on specifics. Sort of like Banno. This can be dangerously deceptive. Banno says that induction is invalid which suggests that there is something wrong with it. You try to counter this by saying that induction is neither valid nor invalid. But does Banno really care? Of course not. He's focusing on his extremely narrow definitions. Nothing can change his mind because what he says is true by definition. Both of you are being too formal. Both of you ignore there's much debate about what logical consequence is. Both of you restrict yourself to Wikipedia and high-school textbooks. I am certainly not the first to speak of inductive validity but is that really important?

    An argument is valid in the general sense of the word if it does not violate the rules of reasoning.

    This is valid:

    1. Some Ps are Qs
    2. All Ps are Qs

    This is invalid:

    1. Some Ps are Qs
    2. No P is Q

    This is also invalid:

    1. Some Ps are Qs
    2. Half of Ps are Qs, half of Ps are not Qs

    It's all relative to the rules of reasoning.
  • David Hume
    You seem to think that if the logical entailment of "Some P's are Q's" is not "No P's are Q's" then it must be "All P's are Q's".Janus

    That's exactly what logical consequence is in the broad sense of the wrong.

    This is simply mistaken; the only logical consequence of "Some P's are Q's" is that some P's are Q's.

    And here you're defining the concept of logical consequence narrowly.
  • David Hume
    I can say the same about you. In fact, I'd probably be more right than you are. A lot of people think they understand what they are talking about; and they do, but very superficially. If I asked you to define logical consequence, I'm pretty sure you'd struggle. Either that or you would define it the same way that I do just unnecessarily narrowly.

    The logical consequence of 2 + 2 is 4. That's what you get when you follow the rules of addition. In the same way, the logical consequence of "Some Ps are Qs" is "All Ps are Qs". That's what you get when you follow the rules of induction. Very simple.

Magnus Anderson

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