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I often hear arguments that go like this but I don't know how to respond to them

I often hear arguments that go like this but I don't know how to respond to them. "Not everyone who is bullied develops behavioral problems or not everyone who is sexually abused develops a severe mental illness such as schizophrenia." These kinds of arguments often imply that because something doesn't happen to everyone then there is no causal relationship between a stimulus and an event. But that seems wrongheaded because though not every ball falls into a pocket after a break in a game of pool that doesn't mean that the cue ball/stick along with the person making the break didn't cause those balls to fall in the pockets. You could also use the same form of argument to argue against more popular beliefs such as the idea that soldiers experience PTSD because of their wartime experiences. So what exactly is wrong with those kinds of arguments assuming I am right in believing they are wrongheaded?

I notice that your question hasn't been answered yet, but it has been waiting for one for a while. I feel a little out of my depth here, but just to provoke some further response(s). I'll take a shot.

Your question is really about what it means to say that something causes something else. If we think of causation as "deterministic," then the laws of causality work in such a way as to have it be that a given cause will always produce a given effect, and the appearance of this effect can be wholly explained in terms of that cause. There are some scientific fields that seem to work this way--classical mechanics, for example. But then, even in the field of physics, it seems that at some levels this (deterministic) conception of causation seems not to apply--for example, within quantum mechanics. Those who explain what is called the "indeterminacy" at this level might explain it in different ways, but at least in terms of explaining and predicting, it looks like the simplicity of a deterministic model of causation is problematized here.

But if you look at most sciences outside of physics, the very notion that causal explanations are deterministic does not apply. Consider a widely accepted and thoroughly scientifically examined example: smoking causes cancer. Does this causal claim imply that either absolutely everyone who ever smokes gets cancer, or else the claim is false? Of course it doesn't! The same lack of complete determinism may be observed in most of medicine--but that does not prove that "medical science" is somehow a misnomer.

But now extend that to the cases you are asking about. The explanation of the prevalence of PTSD among soldiers and former soldiers is very obviously to be explained by their exposure to the horrible things that they experienced in war zones. Does this causal explanation require that everyone who is in a war zone will get PTSD? Of course not--no more than the idea that every smoker will get cancer (or everyone who falls out of third-story window will die, or everyone who drives when drunk will get in an accident, or ... you get the point). Those who seek to undermine our concerns about bullying or sex abuse with "arguments" like the ones you have mentioned simply do not understand the very nature of causal explanation in the biological or social sciences--and probably don't even understand causal explanation, period (since, as I say, even in some areas of physics deterministic assumptions seem not to apply).

I hope this helps! (Others...?)

I notice that your question hasn't been answered yet, but it has been waiting for one for a while. I feel a little out of my depth here, but just to provoke some further response(s). I'll take a shot. Your question is really about what it means to say that something causes something else. If we think of causation as "deterministic," then the laws of causality work in such a way as to have it be that a given cause will always produce a given effect, and the appearance of this effect can be wholly explained in terms of that cause. There are some scientific fields that seem to work this way--classical mechanics, for example. But then, even in the field of physics, it seems that at some levels this (deterministic) conception of causation seems not to apply--for example, within quantum mechanics. Those who explain what is called the "indeterminacy" at this level might explain it in different ways, but at least in terms of explaining and predicting, it looks like the simplicity of a deterministic model...

Is there a way to prove that logic works? It seems that the only two methods for

Is there a way to prove that logic works? It seems that the only two methods for doing this would be to use a logical proof –which would be incorporating an assumed answer into the question– or to use some system other than logic –thus proving that sometimes logic does not work.

Aristotle gives a nice account of why we must have something "definite in our thinking" and not contradictions in Metaphysics IV. In order to say of something that it is or can be both F and not-F, he writes, we must have successfully identified that thing as the thing that is or can be both F and not-F. But we are in no position to do that if the something both is and is not the something we are talking about, or trying to talk about! So we do not have to abandon the piece of logic, the principle of non-contradiction, in one form, at least, which states that opposite things cannot significantly be said of the same thing. Here, at least, it seems that logic does not break down on the basis of the interesting argument that you gave.

It looks to me as if your question is a version of what epistemologists have come to know as "the problem of the criterion"--in this case, with respect to logic. There have come to be three different ways of responding to this problem (which one could also apply to any other sources of information or reasoning, such as sense perception, memory, or induction): reductionism, which provides evidence for the reliability of the source by getting confirmation for that source from some other source (this is more or less the second option you provide in your question, though I am not sure why that seems to you to show that "sometimes logic does not work"); dogmatism, which essentially says that we can be justified in accepting individual samples from a given source without having any (prior) justification for thinking that the source is reliable (this is more or less the first option you present in your question; and holistic coherence theory, which claims that our justification for thinking that the...

Why do we attempt to avoid fallacies?

Why do we attempt to avoid fallacies?

Fallacies are forms of reasoning that fail to provide support for the conclusions reached via that reasoning. In other words, the premises could all be true, but the conclusion still false. Just because something is a fallacy does not make the conclusion of such reasoning false, however.

For example, here is a (deductive, logical) fallacy with a true conclusion:

  1. If my name is Nicholas D. Smith, then I have a very common last name.
  2. I do have a very common last name.
  3. Hence, my name is Nicholas D. Smith.

All the premises are true, and so is the conclusion, but the reasoning is fallacious (called "affirming the consequent"), because the truth of the premises does not in any way support or ensure the truth of the conclusion. To see this, consider another example of the same sort of inference (affirming the consequent):

  1. If I am swimming, then I am wet.
  2. I am wet.
  3. Hence, I am swimming.

Nah! I live in Portland, Oregon--folks here are wet most of the year from the rain. So even if the first two premises of the little argument above are true, notice that it doesn't "follow" that the conclusion is true. Hence, the truth-value of the conclusion is in no way supported or assured by the premises. That's what it means for something to be a fallacy.

To answer your question now, we attempt to avoid fallacies because we care about what is true and we want to believe what is true and not what is false (at least when we are being reasonable). So we want to avoid reasoning that does not help us (and may actually hinder us) from our pursuit of truth.

Fallacies are forms of reasoning that fail to provide support for the conclusions reached via that reasoning. In other words, the premises could all be true, but the conclusion still false. Just because something is a fallacy does not make the conclusion of such reasoning false, however. For example, here is a (deductive, logical) fallacy with a true conclusion: If my name is Nicholas D. Smith, then I have a very common last name. I do have a very common last name. Hence, my name is Nicholas D. Smith. All the premises are true, and so is the conclusion, but the reasoning is fallacious (called "affirming the consequent"), because the truth of the premises does not in any way support or ensure the truth of the conclusion. To see this, consider another example of the same sort of inference (affirming the consequent): If I am swimming, then I am wet. I am wet. Hence, I am swimming. Nah! I live in Portland, Oregon--folks here are wet most of the year from the rain. ...

If I desire to be a logician what should I do to become that?

If I desire to be a logician what should I do to become that?

Study logic. Then study more logic. And then...study a lot more logic.

And then hope that the world (and job market) somehow gives you the opportunity to study and do logic for a living (because if you are distracted with other things, you will never be as good a logician as you could be with logic as your vocation and avocation, which is how muct academics feel about their subjects.

Study logic. Then study more logic. And then...study a lot more logic. And then hope that the world (and job market) somehow gives you the opportunity to study and do logic for a living (because if you are distracted with other things, you will never be as good a logician as you could be with logic as your vocation and avocation, which is how muct academics feel about their subjects.

Is a "slippery slope" argument the same as a reductio ad absurdum?

Is a "slippery slope" argument the same as a reductio ad absurdum?

No, they're not the same. A "slippery slope" argument is one that tries to show that attempting to make a determination about one sort of case will "slide" into another case very like it, and then another very like that one, and so on, until we reach a point where we are no longer willing to endorse the original strategy. For example, a familiar version of "slippery slope" reasoning holds that if we grant rights to gays, then the next thing that will happen is that we have to grant rights to pedophiles, or those who enjoy bestiality or incest. The inference we are suppose to make is that wwe should not take the first step down the slope, as there will be no stopping all of the steps that follow "once you go down that path." As this example shows, many "slippery slope" arguments are simply fatuous, and as a matter of fact none are actualluy logically valid.

A reductio ad absurdum, however, is a logically valid form of argument. The way this argument form works is in virtue of a certain fact about conditional statements (if p then q). The truth conditions of these statements are such that all instances of this form will be true except when the value of the antecedent (p) is true and the value of the consequent (q) is false. Given this fact about conditionals, if you can prove that a statement (say, r) entails some known falsehood (say, s), then you have provided a logical ground for counting r as false. The most obvious case of this will be one in which a statement (say, t) entails a contradiction (both u and not-u).

No, they're not the same. A "slippery slope" argument is one that tries to show that attempting to make a determination about one sort of case will "slide" into another case very like it, and then another very like that one, and so on, until we reach a point where we are no longer willing to endorse the original strategy. For example, a familiar version of "slippery slope" reasoning holds that if we grant rights to gays, then the next thing that will happen is that we have to grant rights to pedophiles, or those who enjoy bestiality or incest. The inference we are suppose to make is that wwe should not take the first step down the slope, as there will be no stopping all of the steps that follow "once you go down that path." As this example shows, many "slippery slope" arguments are simply fatuous, and as a matter of fact none are actualluy logically valid. A reductio ad absurdum, however, is a logically valid form of argument. The way this argument form works is in virtue of a certain fact...

Hello.

Hello. How do you prove that a certain logical fallacy is a fallacy indeed? Are there "fallacies" about which there is a controversy if it is a fallacy or not? And if in the future, a new fallacy will be discovered, what will be the outline of the proof that one will have to use to prove that it exists? (Just an application of the first question.)

From the point of view of deductive logic, your question is very easily answered: a fallacy is an argument form in which the premises may all be true, but the conclusion false. To prove this, one provides what is called a "counterexample," which is simply a substitution instance that has the above characteristics.

For example, take a fairly common deductive fallacy, called affirming the consequent:

(1) If p, then q.
(2) q.
Therefore,
(3) p.

Here is a counterexample:

If 2+2=5 (p), then 5>3 (q)
5>3.
Therefore, 2+2=5.

In inductive logic, however, fallacies may be controversial, because there can be some unclarity about how to calculate or assign probabilities. An example of this kind of problem (to be brief) can be found in the philosophy of religion. For example, some philosophers have claimed that probability arguments can be used to show that it is more likely than not that our world was created by an intelligent designer, because the likelihood of this world coming to exist without a designer is so small. The problem here is trying to assign the relevant probabilities: the probability that there was an intelligent designer, and the probability of our world coming to exist without a designer. Without a way to fix in a determinate way the relevant probabilities, whether an argument is fallacious may be controversial.

From the point of view of deductive logic, your question is very easily answered: a fallacy is an argument form in which the premises may all be true, but the conclusion false. To prove this, one provides what is called a "counterexample," which is simply a substitution instance that has the above characteristics. For example, take a fairly common deductive fallacy, called affirming the consequent: (1) If p, then q. (2) q. Therefore, (3) p. Here is a counterexample: If 2+2=5 (p), then 5>3 (q) 5>3. Therefore, 2+2=5. In inductive logic, however, fallacies may be controversial, because there can be some unclarity about how to calculate or assign probabilities. An example of this kind of problem (to be brief) can be found in the philosophy of religion. For example, some philosophers have claimed that probability arguments can be used to show that it is more likely than not that our world was created by an intelligent designer, because the likelihood of this world coming to...

Where can I find an exhaustive list of the formal fallacies of definition. I

Where can I find an exhaustive list of the formal fallacies of definition. I need this for my work, for controlling the content of data dictionaries and data models. This class of definitions has to be real, not nominal. Thanks in advance, Malcolm C.

There is a very good entry on definitions in the Stanford Encyclopedia of Philosophy (on-line), and a pretty good review of the various fallacies of definition in Wikipedia.

Happy hunting!

There is a very good entry on definitions in the Stanford Encyclopedia of Philosophy (on-line), and a pretty good review of the various fallacies of definition in Wikipedia. Happy hunting!

In connection with http://www.askphilosophers.org/question/2740, is there a

In connection with http://www.askphilosophers.org/question/2740, is there a similar objection (that it is not coherent) to the question "Can an all powerful God create a rock so heavy that he cannot lift it?"? Or does this paradox suggest that it is not reasonable to posit such a thing as an all powerful God? Thanks in anticipation.

Philosophers have debated this sort of question, but I think the consensus is that the question is not coherent. Being "all-powerful" obviously does not mean being able to do what is logically impossible. Think, instead, of the concept as making God into a being who can do anything that can (in principle) be done. Since lifting a rock of any size can in principle be done, God can always lift the rock. But making a rock so big that it can't in principle be lifted makes no sense at all, hence God's not being able to do that is no indication of not being all powerful, it is just to recognize that the description" a rock so heavy that God can't lift it" is nonsense.

Philosophers have debated this sort of question, but I think the consensus is that the question is not coherent. Being "all-powerful" obviously does not mean being able to do what is logically impossible. Think, instead, of the concept as making God into a being who can do anything that can (in principle) be done. Since lifting a rock of any size can in principle be done, God can always lift the rock. But making a rock so big that it can't in principle be lifted makes no sense at all, hence God's not being able to do that is no indication of not being all powerful, it is just to recognize that the description" a rock so heavy that God can't lift it" is nonsense.

Is it immoral to convince someone of some true proposition P, by exposing them

Is it immoral to convince someone of some true proposition P, by exposing them to what you know to be an unsound or invalid argument? For example if I told my friend: "If it rains, the grass will be wet. The grass is wet, therefore, it rained." Now supposing it really did rain, would it be immoral to use this invalid argument to convince her? If we answer in the affirmative, it would seem to lead to some unpleasant conclusions. For instance, it would be immoral to put a sign in my yard that says "Candidate X for City Commission", because the sign might convince people without offering them a sound argument. But we answer negatively, it would seem to justify deception. Using unsound arguments to convince people would give them at best an unjustified true belief, not knowledge. Is there a middle ground here?

Your question raises some fascinating issues. I think it will help to separate your question into two distinct concerns: (1) Is it immoral to use faulty reasoning to convince someone to believe something? (2) Is it immoral to place people in a situation where they might believe something on the basis of faulty reasoning?

My first instinct is that situations involving (1) are likely to be immoral, whereas those involved in (2) are probably not. In cases of the first sort such as cases where you use poor reasoning to convince someone of something, as Professor Smith notes, there is a degree of deception at work. While most moral philosophers don’t think that deception is always a bad thing, they nonetheless think it is bad absent special justification. We can imagine cases where deception is harmless (as in your example, of using faulty reasoning to get someone to believe it rained, when in fact it did rain), or even beneficial (as could happen when you deceive someone to do something that is good for them – like getting them to go to the doctor, or something). But as a general rule, I think we do have a duty not to deceive people, and using faulty reasoning is a mode of deception.

However, I don’t think that holding that it is immoral to use faulty reasoning to convince someone to believe something commits one to saying it is immoral to place people in a situation where they might themselves engage in faulty reasoning. As a parent, I think I should avoid placing my children in such situations because I have a duty to help them learn and develop strong reasoning skills. But I don’t think this is a duty that exists absent particular relationships. Since in these cases you are not actively deceiving anyone, I don’t think you are necessarily doing anything wrong. We can imagine situations where you probably shouldn’t place people in situations where they might engage in faulty reasoning processes, but my sense is that what will make these situations wrong is something other than “that you have put them in a situation where they might engage in faulty reasoning processes”.

To begin with, I don't accept your example of the political sign. Putting an endorsing sign up in your yard is not an invalid argument--it is simply an expression of your opinion. If someone else is persuaded to vote for a candidate just because you have expressed your opinion in favor of that candidate, then so be it. It won't be the result of a bad or invalid argument--though perhaps their reasoning might be faulted as unsound: If S is going to vote for C, then I should vote for C. S is going to vote for C (I can tell from the sign in S's yard). Hence, I should vote for C. This isn't invalid, but at least the first premise (and perhaps the second, too, should be rejected.) On your main question, however, I do think there is somthing wrong with using invalid arguments (at least ones that we know are invalid) to persuade people, both because it might habituate them into bad reasoning habits more generally, and because it is a kind of seduction. Consider: suppose you really believe...

Can two people be correct if one says, "Two members of the same sex should not

Can two people be correct if one says, "Two members of the same sex should not have the right to get married," and the other says, "Two members of the same sex should have the right to get married"?

I think the only way both people could be right is if they don't mean the same thing by "married." Here is a case that might go like that. Suppose the first person is thinking of marriage as a holy sacrament in their religious sect. According to that sect, same-sex marriage is an abomination. Because of that sect's point of view, then, someone might think that there should be no right of same-sex marriage within that sect. Now, even if that is a strongly held belief of that religious sect, it is quite another thing to try to enforce one religious sect's view of things as a matter of law for the rest of the nation (or world). So someone else might think of marriage as a legal contract between two people, one that protects certain civil rights they can enjoy as a result (such as the right to adopt a child as a married couple, for example). It might be that same-sex marriage is an abomination according to some religious groups, but also should be legally permitted as a civil right.

I think the only way both people could be right is if they don't mean the same thing by "married." Here is a case that might go like that. Suppose the first person is thinking of marriage as a holy sacrament in their religious sect. According to that sect, same-sex marriage is an abomination. Because of that sect's point of view, then, someone might think that there should be no right of same-sex marriage within that sect . Now, even if that is a strongly held belief of that religious sect, it is quite another thing to try to enforce one religious sect's view of things as a matter of law for the rest of the nation (or world). So someone else might think of marriage as a legal contract between two people, one that protects certain civil rights they can enjoy as a result (such as the right to adopt a child as a married couple, for example). It might be that same-sex marriage is an abomination according to some religious groups, but also should be legally permitted as a civil right.

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