When do we need to justify our claims?

[Preno]

This is something that cropped up independently in two different threads here and at IIDB (this thread, however, is quite independent and is not meant to be a reply to either of them). In both cases the person I was talking to said or implied that we need to justify each of our beliefs (if we want to be rational).

This seems to be blatantly false to me. Unless we want to trivialize the notion and say that no-one is ever being rational, it seems obvious that our justifications need to stop somewhere (on pain of circularity). It doesn't appear to make much sense to talk about infinite sequences of justifications (certainly not to assume that every sentence is a member of such a sequence, which is what the catchphrase would imply). And even if there is an infinite sequence of justifications, one would presumably also be under an obligation to justify its existence, etc. (At any rate, it would require a very persuasive argument to sweep all this away, rather than just a flat assertion.) So the question from the title raises itself. Let's break it down in two:

What is a justification and when does it make sense to ask for one (regardless of whether one is obliged to or not)? For example, does it make sense to ask for (is it possible to provide) a justification of sentences like "red balls are red"? How about "water is wet"? I myself would cautiously lean towards a negative answer, at least in the former case (ETA: note, however, that it's not the case that tautologies in general need no justification). I think a justification should be in some sense less "questionable" than the statement being justified - not just any old sentence A which entails B is a justification of B (for example, "B and 1=1" is not). And I am hard put to provide a more obvious statement than this (which would also entail it).

And if one claims / believes* something, when is one under an obligation to do provide a justification in order to be rational (assuming it makes sense to ask for one)?

ETA: I realize it's non-trivial to say something non-trivial on this topic, but please no "extraordinary claims require extraordinary evidence".



* I couldn't decide which to use. I would prefer to talk about claiming something, but then the problem is that while I don't need to justify to myself that Jack murdered Jill if I saw them, you are certainly entitled to ask for more justification, in addition, it may be more "rational" for me to prefer persuasiveness over validity. Otoh, framing the question in terms of beliefs doesn't intuitively sound right, as justifying something is primarily a public process, plus if the same person both provides the justification and evaluates it, it seems like what we're dealing with is a justification of the belief's consistency with other beliefs held by the person, rather than of the belief itself.

And, of course, when it comes to "being rational", we also want to abstract from obvious ulterior motives. Perhaps "in order for my argument to be rational" or something.

[Linus]

So the question from the title raises itself. Let's break it down in two:

What is a justification and when does it make sense to ask for one (regardless of whether one is obliged to or not)? For example, does it make sense to ask for (is it possible to provide) a justification of sentences like "red balls are red"? How about "water is wet"? I myself would cautiously lean towards a negative answer, at least in the former case (ETA: note, however, that it's not the case that tautologies in general need no justification). I think a justification should be in some sense less "questionable" than the statement being justified - not just any old sentence A which entails B is a justification of B (for example, "B and 1=1" is not). And I am hard put to provide a more obvious statement than this (which would also entail it).
I would take justification to mean an idealized account of how someone who does not initially believe in the (likely) truth of a statement might come to believe it through valid reasoning. By "idealized account" I mean a hypothetical account rather than a historical account of how someone actually came to believe the statement. I have left it unspecified who it is that this account of belief-change should concern and what beliefs this person is allowed to start from, because I cannot think of a single answer that fits all uses of justification. Sometimes I guess we expect the justification to account for how a person with our own beliefs (minus the statement to be justified, if we already believe) might come to believe the statement. Sometimes we want to know how a believer in the statement might come to believe the statement, starting from his or her actual beliefs minus the statement in question.
And if one claims / believes* something, when is one under an obligation to do provide a justification in order to be rational (assuming it makes sense to ask for one)?
Perhaps one always needs to justify (w.r.t. the previous body of beliefs) the addition of a new belief in order for that addition to rational? On this view, my adoption of my core beliefs (e.g. in the high reliability of certain kinds of inductive reasoning) was irrational, but given those core beliefs the addition of scientifically established conclusions was hopefully rational.

[GenesisNemesis]

When we think they are logical.

[SMS]

This is something that cropped up independently in two different threads here and at IIDB (this thread, however, is quite independent and is not meant to be a reply to either of them). In both cases the person I was talking to said or implied that we need to justify each of our beliefs (if we want to be rational).


It assumes that rationality requires epistemic norms.


This seems to be blatantly false to me. Unless we want to trivialize the notion and say that no-one is ever being rational, it seems obvious that our justifications need to stop somewhere (on pain of circularity).

Usually people will argue that sense experience is reliable. Thence, we have prima facie justification for what we come to believe through our senses. Notably, this has subtopics that need different approaches such like testimony, evidence, the unusual, etc. But, it does help because it largely does allow for sweeping justifications.

[Kissaki]

Any absolute claim needs to be justified. For example, "there is no god" needs to be justified every bit as much as "there is a god", because although the former takes the negative position, it does so absolutely, and thus becomes a positive statement. One does not need justification to believe a negative, though, unless there is evidence in favour of the positive. In which case one must have a justification to discount the evidence, either through counter-evidence, or perhaps different interpretations of the same evidence.

[Flying Buttress]

When
a) they are not self-evident, and
b) we wish to be taken seriously

[Preno]

I would take justification to mean an idealized account of how someone who does not initially believe in the (likely) truth of a statement might come to believe it through valid reasoning.I can agree with that.
Perhaps one always needs to justify (w.r.t. the previous body of beliefs) the addition of a new belief in order for that addition to rational? On this view, my adoption of my core beliefs (e.g. in the high reliability of certain kinds of inductive reasoning) was irrational, but given those core beliefs the addition of scientifically established conclusions was hopefully rational.But surely there is also an obligation to question one's "old" beliefs, too, no? Otherwise, it would be perfectly rational if we just kept adding more and more beliefs without ever revising our original ones. It would, for example, imply that you are under no obligation to change your common-sense views about time when faced with relativity.
Any absolute claim needs to be justified. For example, "there is no god" needs to be justified every bit as much as "there is a god", because although the former takes the negative position, it does so absolutely, and thus becomes a positive statement. One does not need justification to believe a negative, though, unless there is evidence in favour of the positive. In which case one must have a justification to discount the evidence, either through counter-evidence, or perhaps different interpretations of the same evidence.That sounds interesting, but I don't think I understand what you mean by absolute/positive statements. I don't see any natural way of specifying some special class of "positive" statements. What does it mean to "take a position absolutely"? Would you say that all statements that aren't preceded by "perhaps", "likely", etc. are absolute?

[Kissaki]

That sounds interesting, but I don't think I understand what you mean by absolute/positive statements. I don't see any natural way of specifying some special class of "positive" statements. What does it mean to "take a position absolutely"? Would you say that all statements that aren't preceded by "perhaps", "likely", etc. are absolute?

An absolute statement would be something like this:

"His car is red."

Compare with:

"I believe his car is red."

...which is not an absolute sentence (except in the sense that I categorically state that this is indeed what I believe, but it is not an absolute sentence with respect to the car).

It is also a positive claim, as all absolute sentences are. Whether a claim is positive or negative has to do with burden of proof: this is important as you can never prove a negative. I can, for example, say that there are such things as unicorns if I have evidence of their existence, but I can never say that there is not such a thing as a unicorn, because that is something which can never be proven. That there is reason to believe, and believe strongly that there is no such thing, is another matter. But to make a positive statement out of it and stating categorically that there are, indeed, no unicorns anywhere in the universe, is a fallacy. That would imply that the negative has been proven, and that can never happen in such a case.

In specific situations, however, you can prove a negative. For example, I can prove that I was not in Australia yesterday at seven o'clock EST because I can prove that I was in Norway at that time. But there is a reason why the burden of evidence lies with the prosecution.

[Preno]

Why would I never be able to prove a negative (unless you're using a standard of proof by which one can never prove any "empirical" statement)? For example, that all electrons repulse each other?

[Berthold]

In specific situations, however, you can prove a negative. For example, I can prove that I was not in Australia yesterday at seven o'clock EST because I can prove that I was in Norway at that time. But there is a reason why the burden of evidence lies with the prosecution.
This does, however, contain the assumption that bilocation is utterly impossible. :cool:

[Kissaki]

Why would I never be able to prove a negative (unless you're using a standard of proof by which one can never prove any "empirical" statement)? For example, that all electrons repulse each other?
"All electrons repulse eachother" is a positive statement. "Electrons do NOT repulse eachother" would be the negative.


This does, however, contain the assumption that bilocation is utterly impossible. :cool:
:p
Of course, that is actually true. Which goes to show that you can prove certain things beyond a reasonable doubt, but never beyond any which doubt.

[Preno]

Why would I never be able to prove a negative (unless you're using a standard of proof by which one can never prove any "empirical" statement)? For example, that all electrons repulse each other?"All electrons repulse eachother" is a positive statement. "Electrons do NOT repulse eachother" would be the negative.Wrong. "There is no pair of electrons that don't repel each other". It seems you yourself are confused about your own distinction.

[Kissaki]

Why would I never be able to prove a negative (unless you're using a standard of proof by which one can never prove any "empirical" statement)? For example, that all electrons repulse each other?"All electrons repulse eachother" is a positive statement. "Electrons do NOT repulse eachother" would be the negative.Wrong. "There is no pair of electrons that don't repel each other". It seems you yourself are confused about your own distinction.
You still don't seem to understand. "All electrons repulse eachother" is indeed a positive sentence (how is it not?). It isn't positive as in "good", "true" or "optimistic", nor is it negative as in "bad", "false" or "pessimistic", which seems to be the misunderstanding you are labouring under. "There is no pair of electrons wherein the electrons do not repel eachother (fixed grammar)" is likewise a positive statement, but based on a negative position, and hence fallacious until you conclusively prove that it is inherent in the nature of electrons to repel eachother without exception. A brief explanation of negative/positive in terms of argument would be as follows:

"X is true" - positive statement
"X is false" - negative statement

Hence, "all electrons repulse eachother" is a positive statement, because you assert as true that "all electrons repulse eachother".

[James T]

As to the OP, its just self-flagellation.

For positive negative "table is" or "table isn't", I'd be surprised if someone could successfully argue a distinction they actually lived by.

I'm entirely comfortable that proof of a negative is negligibly different from a positive. Those who feel you can't just haven't questioned just how much they rely on the fact (prove air is not poisonous ... or stop breathing eh) that they happily belief negatives proven.

[Preno]

You still don't seem to understand. "All electrons repulse eachother" is indeed a positive sentence (how is it not?). It isn't positive as in "good", "true" or "optimistic", nor is it negative as in "bad", "false" or "pessimistic", which seems to be the misunderstanding you are labouring under.You're right, I don't understand, but I am not conflating "negative" with either of those. You clearly implied that you consider "there are no unicorns" to be a negative statement. Why do you not consider "there are no pairs of electrons that don't repulse each other" a negative statement, too? I don't understand. It has the same form.
"There is no pair of electrons wherein the electrons do not repel eachother (fixed grammar)" is likewise a positive statement, but based on a negative position,Now you're just multiplying the distinctions you need to explain.
and hence fallacious until you conclusively prove that it is inherent in the nature of electrons to repel eachother without exception. A brief explanation of negative/positive in terms of argument would be as follows:

"X is true" - positive statement
"X is false" - negative statementThis distinction doesn't seem to e coherent, as "(not X) is true" is equivalent to "X is false".
Hence, "all electrons repulse eachother" is a positive statement, because you assert as true that "all electrons repulse eachother".When I say that there are no unicorns, I also assert as true that "there are no unicorns", what's the problem? By this logic, every statement is positive (because X is equivalent to "X is true").

[SophistiCat]

An absolute statement would be something like this:

"His car is red."

Compare with:

"I believe his car is red."

I see no difference between the two statements. When you make a meaningful assertion, the presumption is that you are communicating what you believe to be true. If you do not, in fact, believe that the car is red, then either sentence is a lie.

Perhaps the difference that you had in mind is that the first sentence makes a statement about a car, while the second statement makes a statement about your beliefs. The first statement might be in need of a justification, while the second statement cannot be justified in principle, neither to yourself (you cannot doubt that you believe what you believe), nor to anyone else (uttering a sentence like that is all you can do to let people on what you believe). But this is all too obvious.

If you are aiming for a distinction in certainty, then I don't agree that uncertain propositions do not need justification. If you hear that there is a 50% chance of rain today, you will still want some justification for that claim (such as, for instance, the fact that the claim is made by professional meteorologists, based on their best measurements and calculations, rather than by your 5-year old niece, based on a hunch).


"X is true" - positive statement
"X is false" - negative statement

Hence, "all electrons repulse eachother" is a positive statement, because you assert as true that "all electrons repulse eachother".

"It is true that all electrons repel each other" - positive statement.

"It is false that some electrons attract each other" - negative statement? If not, why not?

You still haven't meaningfully defined positive vs. negative statements, except circularly, in terms of the burden of proof. But that's what Preno is asking: which statements carry the burden of proof?

[Kissaki]

As to the OP, its just self-flagellation.

For positive negative "table is" or "table isn't", I'd be surprised if someone could successfully argue a distinction they actually lived by.

I'm entirely comfortable that proof of a negative is negligibly different from a positive. Those who feel you can't just haven't questioned just how much they rely on the fact (prove air is not poisonous ... or stop breathing eh) that they happily belief negatives proven.

The thing is that you have to prove the air is poisonous in the first place in order to say it is poisoned. In your example here, you are asking to prove a negative. Which you rightly refrain from doing.

[Kissaki]

You're right, I don't understand, but I am not conflating "negative" with either of those. You clearly implied that you consider "there are no unicorns" to be a negative statement. Why do you not consider "there are no pairs of electrons that don't repulse each other" a negative statement, too? I don't understand. It has the same form.
Ah, but that is not what you said. "There are no pairs of electrons that do not repulse eachother" is indeed a negative, but what you said was "all electrons repulse eachother" -- which is a positive.


"There is no pair of electrons wherein the electrons do not repel eachother (fixed grammar)" is likewise a positive statement, but based on a negative position,Now you're just multiplying the distinctions you need to explain.
Yes, and I will try to do so: the notion of there being no pair of electrons etc., is indeed a negative position. But when you state absolutely that there are indeed NO electrons that do not repel eachother (not just "no known", but categorically "none"), you have made an absolute, positive claim, but one based on negative evidence. If I was to expand the sentence it might become a bit more clear:

"I know for a fact that there are no instances of X."



When I say that there are no unicorns, I also assert as true that "there are no unicorns", what's the problem? By this logic, every statement is positive (because X is equivalent to "X is true").
Negative sentences are based on the positive, in the sense that you can say "X is true", and by demonstrating that this is not the case, I can say "X is false". But I have only demonstrated this for this particular case. It does not give me the basis to say that "X can NEVER be true".

[Kissaki]

I see no difference between the two statements. When you make a meaningful assertion, the presumption is that you are communicating what you believe to be true. If you do not, in fact, believe that the car is red, then either sentence is a lie.
You're right, I guess that was a bad example.


Perhaps the difference that you had in mind is that the first sentence makes a statement about a car, while the second statement makes a statement about your beliefs. The first statement might be in need of a justification, while the second statement cannot be justified in principle, neither to yourself (you cannot doubt that you believe what you believe), nor to anyone else (uttering a sentence like that is all you can do to let people on what you believe). But this is all too obvious.
No, the distinction I had in mind was more in this vein:

"This is his car" <- can be proven wrong

"This is not his car" <- cannot be proven wrong

And it is for this reason, perhaps on a tangent, that claiming a negative absolutely is fallacious, strictly speaking -- but of course we do it all the time, in eg. "there is no Santa Claus".



If you are aiming for a distinction in certainty, then I don't agree that uncertain propositions do not need justification. If you hear that there is a 50% chance of rain today, you will still want some justification for that claim (such as, for instance, the fact that the claim is made by professional meteorologists, based on their best measurements and calculations, rather than by your 5-year old niece, based on a hunch).
No, I was not aiming for such a distinction.



"It is true that all electrons repel each other" - positive statement.

"It is false that some electrons attract each other" - negative statement? If not, why not?
The former is a positive statement. The latter is a negative position, but stated absolutely, hence a positive statement requiring evidence, but one for which there can never be absolute proof.


You still haven't meaningfully defined positive vs. negative statements, except circularly, in terms of the burden of proof. But that's what Preno is asking: which statements carry the burden of proof?
In short: positive sentences carry the burden of proof. In courts of law, it is always the one making the statement, "he is guilty" who has the burden of proof. The one saying "he is not guilty" can only ever prove it for specific implications, like "he did NOT kill Dr. Black with the candlestick in the kitchen at 9pm". He can never prove that he never had anything to do with it by way of design or plot. Therefore, anyone asking that this be proven first is asking for negative proof.

The defendant can thus maintain his position that he never did it without the burden of proof, but he cannot say that he would never do it. That would be drawing conclusions on a precedent and rejecting the possibility of anything breaking with that precedent. Again, without evidence there is no reason to assume that he would, but there is no justification in stating this as an absolute.

I am reminded here of the creationist argument that "since the Urey/Miller experiment did not produce life, we can conclude that life cannot be produced in a laboratory". Which, of course, is a false conclusion.

[SophistiCat]

"This is his car" <- can be proven wrong

"This is not his car" <- cannot be proven wrong

Um, why not? I don't think the second statement is any less falsifiable than the first.

Anyway, are you now saying that it is just unfalsifiable statements that don't need to be justified?

The former is a positive statement. The latter is a negative position, but stated absolutely, hence a positive statement requiring evidence, but one for which there can never be absolute proof.

I am still not clear as to what an absolute statement is.

In short: positive sentences carry the burden of proof. In courts of law, it is always the one making the statement, "he is guilty" who has the burden of proof. The one saying "he is not guilty" can only ever prove it for specific implications, like "he did NOT kill Dr. Black with the candlestick in the kitchen at 9pm". He can never prove that he never had anything to do with it by way of design or plot. Therefore, anyone asking that this be proven first is asking for negative proof.

The defendant can thus maintain his position that he never did it without the burden of proof, but he cannot say that he would never do it. That would be drawing conclusions on a precedent and rejecting the possibility of anything breaking with that precedent. Again, without evidence there is no reason to assume that he would, but there is no justification in stating this as an absolute.

First of all, let's not confuse justification with logical proof. There is only a very restricted class of statements that can be expected to be proven logically, and even then the premises may stand in need of justification, and perhaps even logic itself. (I think that logic cannot be in need of justification, but that's a question to be considered, anyway.)

Second, criminal court is a very special case in terms of what is taken to be a justification, aka the burden of proof. I think Preno's question concerned philosophical justification, which is not the same.

[James T]

The thing is that you have to prove the air is poisonous in the first place in order to say it is poisoned.:dunno: odd reply.

My point is "The air (or food or whatever) is not poisonous" is something I rely on continuing to be true. Like most people.

The rock will continue to behave rocklike etc.

In accepting induction, we end up accepting a large amount of proof by both positive and negative examples to the extent that these are only semantically different.

So, for someone who says it is possible to prove a positive but not a negative I say ... BULLSHIT!

[Linus]

But surely there is also an obligation to question one's "old" beliefs, too, no? Otherwise, it would be perfectly rational if we just kept adding more and more beliefs without ever revising our original ones. It would, for example, imply that you are under no obligation to change your common-sense views about time when faced with relativity.
Ah, yes, when adding beliefs that are inconsistent with one's current beliefs, I envision that a rational person would reexamine the justifications for the beliefs that lead to the inconsistency and weigh them against the justification for the statement that is a candidate to a new belief. That is, suppose I aspire to be rational, believe that A-and-B, and now want to examine C = not-B as a candidate for a new belief. Then I would compare the best known justification of B from A and weigh it against the best known justification of not-B from A. In other words, adding beliefs is not a monotonic process, addition of C also results in the "subtraction" of not-C (if not-C is a belief and it is realized that it is inconsistent with C).

[SMS]

No, the distinction I had in mind was more in this vein:

"This is his car" <- can be proven wrong

"This is not his car" <- cannot be proven wrong

And it is for this reason, perhaps on a tangent, that claiming a negative absolutely is fallacious, strictly speaking -- but of course we do it all the time, in eg. "there is no Santa Claus".


I'm puzzled as to how the one can be 'proven' wrong and the other cannot. The first would need a basis to say that it is his car as opposed to hers. Yet, once you have that criteria, then you can also show that the car is not hers.

(assuming that the car does not belong to both him and her)

[Linus]

No, the distinction I had in mind was more in this vein:

"This is his car" <- can be proven wrong

"This is not his car" <- cannot be proven wrong

And it is for this reason, perhaps on a tangent, that claiming a negative absolutely is fallacious, strictly speaking -- but of course we do it all the time, in eg. "there is no Santa Claus".
Surely both of these statements can be proven/disproven, at least to the satisfaction of a court of law, under a usual understanding of what it means to own a car, lest it would be impossible to settle legal disputes about car ownership? Despite your two puzzling examples about car ownership, I wonder if the distinction you have in mind is not the distinction between

"All x that are As are also Bs"
"There does not exist any x that is both an A and a non-B"

on the one hand and

"Some x are both As and non-Bs"
"This particular x is an A and a non-B"

on the other. That is, is your distinction really the distinction between universal statements about all individuals/objects of a given type vs. statements about particular individuals/objects?