Category: Burden of Proof

Harry Reid on Burden of Proof

Here:

Harry Reid, the top Democrat in the Senate, was asked by CNN’s Dana Bash this week if he regretted his 2012 accusation on the Senate floor that GOP presidential nominee Mitt Romney “hasn’t paid taxes for ten years.” Reid presented no evidence at the time and claimed he didn’t need any: “I don’t think the burden should be on me. The burden should be on him. He’s the one I’ve alleged has not paid any taxes.”

Ad Ignorantiam and the Law

The day before yesterday I wrote,

In a criminal case the probative bar is set very high: the accused has to be shown guilty beyond a reasonable doubt.  Here too there seems to be a legitimate appeal to ignorance: if it has not been shown that the defendant is guilty beyond a reasonable doubt, the conclusion to be drawn is that he is not guilty.

We will have to examine this more carefully in a separate post.

Herewith, the separate post.  Plainly, the following is an invalid argument:

1. It was not proven beyond a reasonable doubt that it was Smith who killed Jones.

ergo

2. Smith did not kill Jones.

Examples like this appear to support the idea that some appeals to ignorance (or arguments from ignorance) are reasonable and non-fallacious.  According to Douglas N. Walton,

. . . the criminal law presumes that a person is not guilty if he has not been shown to be guilty.  This is an ad ignorantiam form of argument, but it can be reasonable in the context of the rules of argument in the criminal law.  (Informal Logic: A Handbook for Critical Argumentation, Cambridge UP, 2007, 20th ed., p. 47)

I wonder if this is right. Which better represents a criminal process that terminates in an acquittal?  Is it the above argument or the following argument?

1. It was not proven beyond a reasonable doubt that it was Smith who killed Jones.

ergo

3. The presumption of Jones' innocence has not been defeated and Jones is in the eyes of the law not guilty.

I now think it is the second argument.  But note that (i) the second argument is valid, and (ii) there is no appeal to ignorance in the second argument.  The validity of the second, enthymematic, argument is obvious when we make explicit the tacit assumption, namely, that

4. If the accused in a criminal proceeding has not been proven to be guilty of the crime with which he is charged beyond a reasonable doubt, then the presumption of innocence has not been defeated and the accused is in the eyes of the law not guilty.

So the second argument is (formally) valid.  It also does not represent an appeal to ignorance.  One is not arguing that:  Jones is not guilty in reality (as opposed to in the eyes of the law) because it has not been proven that he is not guilty.  One is arguing  that the presumption of innocence has not been defeated.  The following are different propositions:

a. Jones is not guilty

b. Jones' presumption of innocence (POI) has not been defeated.

It ought to be obvious that they are different.  They are logically independent.  Each is consistent with the negation of the other.  Thus the following sets are consistent dyads: {Jones is guilty; Jones' POI has not been defeated}, {Jones is not guilty; Jones' POI has been defeated}.

Conclusion

According to Walton, ". . . the criminal law presumes that a person is not guilty if he has not been shown to be guilty.  This is an ad ignorantiam form of argument . . ."  I think this betrays a misunderstanding of the notion of presumption, and in particular, presumption of innocence. 

The presumption is not that a person is not guilty if he has not be shown to be guilty; the presumption is that he is to be treated as if not guilty, if he has not been shown to be guilty.  In the case of O. J. Simpson, almost everyone agrees that he is guilty of murdering Nicole Brown Simpson and Ronald Goldman.  Yet he was found not guilty.  Obviously, there is a difference between being not guilty (being not guilty in fact) and being found not guilty (being not guilty in the eyes of the law).  The presumption of innocence was not defeated in that trial.  But that is consistent, as I argued above, with the accused's being guilty.

It is therefore a mistake to think that the POI procedural rule embodies an appeal to ignorance. And since there is no appeal to ignorance here, there is no reasonable or non-fallacious appeal to ignorance.

UPDATE:  Dave Bagwill writes,

 

My grand-dad did not mince words, nor did he suffer fools. When I tried to trick him with verbal technicalities, he would accuse me of "trying to pick the fly shit out of the pepper".

 He would have said that about your latest post 'On Ad Ignorantiam and the Law', but he would have been wrong. You made some very fine, fine distinctions in that post that really cut to the heart of the matter. Thanks, and well done. (I've used that book by Walton for years and generally found it useful.)

You're welcome, Dave.  My response to your grandfather would be to make yet another distinction, one between hairsplitting and the drawing of necessary distinctions, and then distinguish different kinds of hairsplitting.

One sort of hairsplitting is  to make distinctions that correspond to nothing real, distinctions that are merely verbal. The 'distinction' between a glow bug and a fire fly, for example, is merely verbal: there is no distinction in reality. A glow bug just is a firefly. Similarly there is no distinction in reality between a bottle's being half-full and being half-empty. The only possible difference is in the attitude of someone, a drunk perhaps, who is elated at the bottle's being half-full and depressed at its being half-empty.

But this is not what people usually mean by the charge of hairsplitting. What they seem to mean is the drawing of distinctions that don't make a practical difference. But whether a distinction makes a practical difference depends on the context and on one's purposes. The truth of the matter is that there are very few occasions on which the charge of hairsplitting is justly made. On almost all occasions, the accuser is simply advertising his inability to grasp a distinction that the subject-matter requires.

Walton may be the premier writer on informal logic.  His book is apparently well-thought-of.  2007 saw the 20th edition.  I'd guess there have been editions since then.

 

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Burden of Proof, Appeal to Ignorance, Safety Considerations, and God

Presumption and Burden of Proof

Firearms instructors sometimes say that every gun is loaded.  That is plainly false as it stands, but a wise saying nonetheless if interpreted to mean: every gun is to be presumed loaded until proven unloaded. Presumptions are procedural rules.  To presume every gun to be loaded is to adopt a procedural rule to treat every gun as if it is loaded regardless of how antecedently likely it is that it is loaded.  Suppose the likelihood is near zero: I examined the gun carefully an hour ago and I found it to be unloaded.  Nevertheless, the presumption that it is loaded remains in force.  I continue to behave as if it is loaded.  For example, I don't point the gun at anything unless I want to destroy it.

I conclude that to presume that p is not to assert that p is true, nor to assert that p is probably true, nor to assume that p is true, but to decide to act as if p is true.  A presumption, then, is not a proposition, although it embeds one.  A presumption is something like a decision.  More precisely, a presumption is the accusative of an act of presuming, an accusative that is not itself a proposition, but embeds one. 

A presumption is not like a belief in the following important respect.  To presume that a gun is loaded or that a man is innocent is not to believe that it is or that he is.  To believe that p is to believe that p is true.  But to presume that p is not to presume that p is true; it is to act as if p is true without either accepting or rejecting p.  To presume that Jones is innocent until proven guilty  is not to believe that he is innocent until proven guilty; it is to suspend judgment as to guilt or innocence until sufficient evidence is presented by the prosecution to warrant a verdict one way or the other.  When I presume that p, I take no stand as to the truth-value of p — I neither accept nor reject p — what I do is decide to act as if p is true.

Presumptions must be defeasible.  (I suspect that an indefeasible presumption is no presumption at all.) The presumption of being loaded is defeated in a particular case by carefully examining the gun and showing that it is unloaded.  So while a presumption is not a proposition, it embeds a proposition that can be shown to be false.  Defeasible presumption and burden-of-proof are correlative notions.  (They are like rights and duties in this respect but also in that both are normative notions.)  In a court of law, for example, if the accused enjoys a presumption of innocence, as he does in the Anglosphere, then the accuser bears a burden of proof, a burden which, if properly discharged, defeats the presumption. 

Appeal to Ignorance?

So if  person A claims to person B that a certain gun is unloaded, the burden of proof is on A to show that it is unloaded; person B does not bear the burden of proving that it is loaded.  It is not just that he bears a lesser burden'; he bears no burden. Indeed it seems that B would be within his epistemic rights were he to claim that his ignorance of whether or not the gun is loaded is good evidence of its being loaded.  But this is an appeal to ignorance.  It has not been shown that the gun is unloaded; ergo, the gun is loaded.

It has not been shown that ~p; therefore p gives us the form of the ad ignorantiam 'fallacy.'  Construed as a deductive argument, it is clearly invalid.  Construed as an inductive argument, it will be in many cases weak.  For example, suppose the gun is straight from the manufacturer and right out of the box.  Then the probability of its being loaded is very low, and the argument: This gun out of the box has not been shown to be unloaded; ergo, this gun is loaded is very weak.

Nevertheless, safety considerations dictate a defeasible presumption in favor of every gun's being loaded, whether out of the box or not, a presumption that places the onus probandi on the one who maintains the opposite.  So one might  conclude that the appeal to ignorance in this case is reasonable even though the argument is deductively invalid and inductively weak.

The situation is similar to that in a court of law.  The defendant is presumed innocent until proven guilty, so the burden of proof rests on either the state in a criminal proceeding, or on the plaintiff in a civil trial.  In a criminal case the probative bar is set very high: the accused has to be shown guilty beyond a reasonable doubt.  Here too there seems to be a legitimate appeal to ignorance: if it has not been shown that the defendant is guilty beyond a reasonable doubt, the conclusion to be drawn is that he is not guilty.

We will have to examine this more carefully in a separate post.

Safety Considerations

There are 'safety' considerations in both the gun example and the law example.  It is because we want to be on the safe side — and not get shot — that we presume every gun to be loaded. "Better that a hundred guns be unnecessarily examined than that one sentient being be accidentally shot."

And it is because we want to be on the safe side — and not sentence an innocent person — that we presume the accused to be innocent until proven guilty.  "Better that a hundred guilty people go free than that one innocent person be wrongly convicted."

But now what about God?  Don't safety considerations apply here as well? If God exists, then our ultimate happiness depends on getting into right relation with him.  So why can't one make a legitimate appeal to ignorance here?  Now of course from the fact that no one has proven that God does not exist, it does not follow that God exists.  That is an invalid deductive argument.  That would be a truly fallacious instance of ad ignorantiam.  But it is also invalid to infer than a gun is loaded because it hasn't been proven to be unloaded, or that a man is innocent because he hasn't been proven to be guilty.  It just doesn't follow in any of these cases.  And yet we reasonably consider the gun loaded and we reasonably find the accused to be innocent.  And so why can't we reasonably presume God to exist on the basis of the fact that he hasn't been shown not to exist?  If the burden of proof rests on the one who claims that gun is unloaded, why doesn't the burden of proof rest on the one who claims that God is nonexistent?  We don't want to get shot, but we also don't want to lose our ultimate beatitude — if ultimate beatitude there be. 

You can't say that that the burden of proof rests on the theist because he is making a positive claim; for there are positive claims that need no proof.  And you can't say that the burden of proof rests on the theist because he is making an existential claim; for there are existential claims that need no proof. If you claim that extraterrestrial intelligent beings exist, then the burden is on you.  But if you claim that there are Saguaro cacti in Arizona, then the burden of proof is not on you but on the one who denies it. Nor can you say that the burden rests on the theist because he is controverting the widely-accepted; the consensus gentium is that God exists.

Earlier I argued that we shouldn't bring BOP considerations into the God discussion at all.  But if we do, why doesn't the BOP rest on the atheist?

Pigliucci's Confusion

Massimo Pigliucci thinks that if one understands who bears the burden of proof in a trial, then one ought to see right away that the burden of proof rests on the theist.  For, "the burden of proof is always on the party making a positive claim, not on the one making a negative one."  This strikes me as confused.  It is true that the party making a complaint or bringing a charge is making a positive claim, but this is not the reason why the BOP rests on the accuser.  It rests on the accuser because of the presumption of innocence that the accused enjoys.  The BOP rests on the accuser not because his claim is positive but because of the procedural rule enshrined in our system of law according to which one is presumed innocent until proven guilty.

It is not true that the BOP is always on the one who makes a positive claim.   'That hillside is studded with Saguaro cacti' said to my hiking companion needs no proof.  I shoulder no probative burden when I make a commonplace observation such as that. Therefore, the following is an unsound argument:

Everyone who make a positive claim bears a BOP.
The theist makes a positive claim.
ergo
The theist bears the BOP in his debate with the atheist.

I argued above that if BOP considerations are relevant to the God debate, then the BOP is on the atheist.  To appreciate the argument I gave, you have to realize that the God question is not merely theoretical.  It is a practical question.  In that respect it is like the gun safety and court room cases.  My interest in whether or not a particular firearm is loaded or unloaded is not merely theoretical, or I should say, not at all theoretical.  It is a practical interest in maintaining the health and physical integrity of myself and the people around me.  Similarly with the law.  If you are accused of homicide you are in deep trouble and face the loss of your liberty or your life.  Arguably, the God question is in the same boat.

So I invite you to accept one or the other of the following conclusions.  The BOP is borne by the atheist.  BOP considerations should be kept out of the theist-atheist debate altogether. 

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Disputation and Burden of Proof: A Round with Professor Novak

Novak novotnyI proposed for consideration a bit of dialog:

A: The law of noncontradiction (LNC) is a law of thought merely.

B: I dispute your claim. LNC is not a law of thought merely; it is also a law of extramental reality.

In this example, B disputes what A says by making a counter-claim, a counter-assertion. Both are asserting. It strikes me as foolish to ask who has the burden of proof (BOP). How decide such a question?  I assume that in a dialectical situation like the  above, if BOP considerations are relevant at all, then the BOP is on one side or the other, but not on both, and not on neither.  But there is no non-arbitrary way to place the onus probandi on one side or the other.  Therefore, BOP considerations are a useless detour.  Why not go straight to the question and evaluate the arguments pro et contra?

Suppose you say that the BOP rests on the one who opposes the received or traditional view. Then the BOP would be on A. But if you say that the BOP rests on the one who makes the stronger claim, the more committal claim, then the BOP would be on B.  I don't see how there could be a non-arbitrary assignment of BOP in a dialectical situation like this.  Correlatively, I don't see how it could be non-arbitrarily claimed that there is a defeasible presumption (DP) in favor of A's assertion or of B's. So I suggest we drop the BOP talk!

Lukas Novak's response:

Concerning your dialogue: In my opinion, both A and B bear a burden of proof here. For that reason, it is an unlucky start of a dispute – because it is in fact the  start of two disputes at once, and a dialectical confusion is likely to arise. In order that the dialogue be fruitful, B should not have put forward a negation of A's claim as his own claim, but simply refuse to accept A's claim until proved (this is the meaning of the rule Necessitas probandi incumbit ei qui dicit non ei qui negat – "negare" here has the technical meaning of "to refuse to concede until proved", according to the rules of disputation). If A failed to produce a proof, his case would fail. If he produced one, his case would succeed unless and until B attacked that proof, thus prompting  another argument to "restore" the former one. And so on, until one of the parties failed to do their duty. Only if A was the one who so failed, would it be in place for B to state his opposite meaning as a claim, if he wishes, with the burden of proof incumbent on him

There are three, not two possible dialectical states of a proposition: (i) proved (ii) disproved (iii) neither. The "burden of proof" just means that the default state is (iii).

Perhaps our difference boils down to this: you think that a dispute is about truth or falsity of a proposition, whereas I think that it is about validity or invalidity of rational support of a proposition. Whereas from the former point of view the dialectical situation comes out as symmetric, in the latter view it is inherently asymmetric.

Reply to Novak

Part of our difference here may be due to a different understanding of 'dispute.'  I think Lukas may be using it is a technical way similarly as he uses negare in a technical way.  And perhaps these technical meanings are the same.  When I used 'dispute' in the little dialog above I was using it to mean 'disagree with.'  Lukas seems to be using it to mean 'refuse to concede until argument is provided.' 

Lukas seems just to be assuming that the BOP rests on A who must "produce a proof" otherwise his "case would fail." I take that to mean that A is obliged to give an argument for the claim he has made.  (In my book, an argument is not the same as a proof, although every proof is an argument.)  But, by my lights, if so, then the same goes for B: he too must give an argument for his counterclaim.  B cannot just cross his arms across his chest and say, "I don't have to give an argument for my assertion; it suffices for me to poke holes in your argument.  The BOP is on you, not on me."  This is precisely what I reject.  Otherwise, there would be a presumption in favor of B's claim. But there isn't.  And to insist that there is, is to beg a philosophical question.

I think Lukas is right when he says that, for me, the dialectical situation is symmetric, at least in the example given above, while for him it is asymmetric.

Lukas is also right when he says that, for me, the dispute (disagreement) is about the truth-value of a proposition: Is it true or is it false that LNC is a law of thought merely?  He says that, for him, the disagreement is "about validity or invalidity of rational support of a proposition."

But this needs explaining.  Validity and invalidity are technical concepts from formal logic.  Our present topic, however, is not formal logic, but dialectics.  Lukas seems to think that there are certain procedural rules that govern the conduct of a discussion, and that these rules induce certain rights and duties in the interlocutors.  Thus, he who makes an assertion puts himself under a dialectical obligation to support his assertion with one or more arguments, while the one to whom the assertion is made is under no obligation to support the negation of the asserted proposition: he has the right to do no more than find fault with the arguments for the asserted proposition.

I am skeptical of this entire adversarial model which has its provenience in the court-room situation and makes perfect sense there, but seems to me not appropriate in philosophy which, by my lights, is not a matter of debate or disputation but one of dialogue in which the interlocutors are not out to prove propositions they antecedently accept and do not question, but who aim at arriving at the truth together, a truth that they do not claim to possess, but are seeking.

See also:  Philosophy, Debate, and Dialog

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Parsimony, Burden of Proof, and God

From an e-mail by Spencer Case:

. . . by my lights, parsimony might be a consideration that puts the burden of proof on the theist. Theories that multiply entities unnecessarily are less likely to be true and the theist's theory postulates an entity. Now, it may be that the theist will say that we need God as a first cause or something like that– that could be enough to absolve him of the burden. But in the absence of other reasons for believing in God (known to the interlocutors), the burden of proof would be on the theist.

Let's think about this.  I doubt the usefulness in philosophy of burden-of-proof considerations, at least  when we are discussing such big questions as God, freedom, and immortality.  I also doubt the usefulness in philosophy of considerations of parsimony.  What is parsimony anyway?

Parsimony

Parsimony or Occam's Razor is  a principle of theoretical economy that states or rather enjoins:

   OR. Do not multiply entities beyond necessity.

It is sometimes formulated in Latin: Entia non sunt multiplicanda praeter necessitatem. The principle or rather injunction is presumably to be interpreted qualitatively rather than quantitatively, thus:

   OR*. Do not multiply TYPES or CATEGORIES of entity beyond necessity.

Thus it is not individual entities that are not to be multiplied, but types or kinds or categories of entity.  To illustrate.  Some criticized David Lewis' extreme modal realism on the ground that it proliferates concreta: there are not only all the actual  concreta , there are all those merely possible ones as well.  He responded quite plausibly to the proliferation charge by pointing out that the Razor applies to categories of entity, not individual entities, and that category-wise his ontology is sparse indeed.

'Multiply' is a picturesque way of saying posit. (Obviously, there are as many categories of entity as there are, and one cannot cause them to 'multiply.')  And let's not forget the crucial qualification: beyond necessity.  That means: beyond what is needed for purposes of adequate explanation of the data that are to be explained.  Hence:

OR**  Do not posit types of entity in excess of what is needed for purposes of explanation.

So the principle enjoins us to refrain from positing more types of entity than we need to explain the phenomena that need to be explained. It is obvious that (OR**) does not tell us to prefer theory T1 over theory T2 if T1 posits fewer types of entity than T2. What it tells us is to prefer T1 over T2 if T1 posits fewer types of entity AND accounts adequately for all  the data. So there is a trade-off between positing and accounting.

Spencer tells us that "Theories that multiply entities unnecessarily are less likely to be true . . . ."  I don't think this is right.  Theories that posit entities or types of entity beyond the needs of explanation are uneconomical and to be rejected for this reason.  We prefer simpler theories to save cognitive labor, not because simplicity is the mark of truth (simplex sigillum veri) or even because simpler theories are more likely to be true.  Now it may be that simpler theories are more likely to be true  — how would one show this? — but this is no part of the principle of parsimony as I understand it.  It is a principle of Denkoekonomie.

The defeasible presumption in favor of parsimonious explanations is very much like the defeasible presumption of innocence (POI) in the law.  The accused is presumed innocent until proven guilty even if the probability of his being innocent is low or even near or at zero. The presumption of innocence does not vary with the probability of innocence, and is in fact logically consistent wth guilt.  And of course the presumption of innocence does not entail innocence.

POI is a procedural rule: we proceed in the law as if the accused is innocent even if it is evident that he isn't.  (Suppose 100 reputable winesses observe a man in a non-self-defense situation bludgeoning a woman to death.  There still has to be a trial, the accused will enjoy the POI, and the prosecutors will bear the burden of proof.  It's just that this trial will be very short.)  Similarly, the principle of parsimony is a principle of procedural presumption. (See N. Rescher, Presumption and the Practices of Tentative Cognition, Cambridge UP, 2006. p. 124 ff.)

God

Suppose everything could be explained just as well without God as with God.  Then we would have no reason to posit God as playing an explanatory role.  But it wouldn't follow that God doesn't exist, or even that it is unlikely that God exists.  All that would follow is that we would have no reason to posit God as an explanation of the existence, order, intelligibility of the universe: The 'God hypothesis' would not be rationally motivated.  

Now one point I want to make is that Parsimony is a fairly useless and trivial injunction.  After all, who wants to posit types of entity in excess of what is needed for purposes of explanation?  The real question is what is needed for explanation.  Parsimony gives us no help with this question.  I would argue that God is needed to explain the existence and the intelligibility of the universe.  Now that is a meaty set of issues that cannot be resolved by brandishing the Razor.  We all agree about the Razor.  What we don't agree about is what is necessary for an adequate explanation of what needs explaining.

And so it would be a cheap shot for an atheist to claim that theists violate Parsimony by positing God.  Spencer of course understands this.  For again, the issue is whether the posit is necessary for explanation.

Burden of Proof

Who bears the burden?  Theist or atheist?  The question is senseless or else has a trivial answer: both bear it.  For it is not evident that God exists, nor it is evident that God does not exist.  Neither side can invoke a defeasible presumption.

But there is a defeasible presumption in favor of the reliability of memory as a source of knowledge; so it does make sense to place the burden of proof on one who denies it.

Finally, does parsimony put the burden of proof on the theist as Spencer claims?  No and for two reasons. First, Parsimony is a trivial injunction that, by itself, cannot decide between theism and atheism.  Second, it is either senseless or trivial to ask where the BOP lies in the atheism-theism dispute.

UPDATE  (10/28):  Spencer Case e-mails:  "I think you should make clear to your readers that your post attributes views to me that I do not hold. The part you quote from me is given in a context that is meant to show how my view of burden of proof would apply to a particular dialectical situation where an atheist thought parsimony mattered for the reason I stated. I wasn't actually subscribing to that view of parsimony. My account of what philosophical burden of proof amounts to was the main point of my comments.

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Peter van Inwagen on Burden of Proof in Philosophy

Andrew Bailey sends the following quotations for our delectation:

"(When a philosopher says, "The burden of the proof lies on you", he means, "You must deduce your conclusion from the truths of immediate sensory experience by means of an argument that is formally valid according to the rules of elementary logic; I on the other hand may employ any dialectical tactic I find expedient".)"
 
-PvI, An Essay on Free Will, p.18
 
"Where does the burden of proof lie in a philosophical debate? In a debate of the type we are imagining, the answer is clear–in fact, trivial. The burden of proof lies on the person who's trying to prove something to someone."
 
-PvI, The Problem of Evil, p.46
 
Notice that the thesis encoded in the second is a little different (and much more plausible) than "he who asserts must prove".
I'd have to examine the context, but the second quotation seems to support what I was saying yesterday, namely, that burden-of-proof considerations have no non-trivial role to play in philosophical discussions. 
 
It is quite otherwise in the law, which is where we get the notion of burden of proof (BOP) and the correlative notion of defeasible presumption (DP).  As N. Rescher remarks (Presumption and the Practices of Tentative Cognition, p. 13),  both are at root legal conceptions dating back to Roman law.  Now court-room proceedings are essentially both practical and adversarial:  what is in dispute is not a matter of theory, but a matter bearing upon such things as a person's wealth and liberty.  Thus it makes perfect sense that the BOP should be placed on the plaintiff in a civil case and the state in a criminal case, which is equivalent to granting to the accused a defeasible presumption of innocence.  The onus probandi rests on those who make allegations.  Thus it makes sense within the law to maintain that
 
Necessitas probandi incumbit ei qui dicit non ei qui negat.
The need for proof lies with him who affirms, not him who denies.
 
Now to my way of thinking, philosophy-as-inquiry is never adversarial, and is primarily theoretical.  This is part of my reason for thinking that the fundamentally legal notions of BOP and DP ought not be imported into philosophy-as-inquiry.  It strikes me as very clear that one who makes an accusation bears the burden of proof.  But it is not so clear that one who makes an assertion bears a burden of proof. 
 
Indeed, it is either false or meaningless. For if van Inwagen asserts that there are no modes of being, and I assert that there are, then we both make assertions.  So if he who asserts bears a burden of proof, then we both bear the burden of proof — which trivializes the very notion of BOP.
 
So I am skeptical about the importation of the fundamentally legal concept of BOP from that essentially adversarial and practical dialectical context into philosophy-as-inquiry.  But this is a complicated topic.  I'll say some more tomorrow.
 
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Are Burden-of-Proof Considerations Relevant in Philosophy?

Burden-of-Proof.jpg-550x01. The question this post raises is whether it is at all useful to speak of burden of proof (BOP) in dialectical situations in which there are no agreed-upon rules of procedure that are constitutive of the 'game' played within the dialectical situation.  By a dialectical situation I mean a context in which orderly discussion occurs among two or more competent and sincere interlocutors who share the goal of arriving as best they can at the truth about some matter, or the goal of resolving some question in dispute.  My main concern is with dialectical situations that are broadly  philosophical.   I suspect that in philosophical debates the notion of burden of proof is out of place and not usefully deployed.  That is what I will now try to argue.

2. I will begin with the observation that the presumption of innocence (POI) in an Anglo-American court  of law is never up for grabs in that arena.  Thus the POI is not itself presumptively maintained and subject to defeat.  If Jones is accused of a crime, the presumption of his innocence can of course be defeated, but that the accused must be presumed innocent until proven guilty is itself never questioned and of course never defeated.  The POI is not itself a defeasible presumption.  And if Rescher is right that there are no indefeasible presumptions, then the POI is not even a presumption.  The POI is a rule of the 'game,' and constitutive of the 'game.'  The POI in a court room situation  is like a law of chess.  The laws of chess, as constitutive of chess, cannot themselves be contested within a game of chess.  In a particular game a dispute may arise as to whether or not a three-fold repetition of position has occurred.  But that a three-fold repetition of position results in a draw is not subject to dispute. The reason there is always a definite outcome in chess (win, lose, or draw) is precisely because of the non-negotiable chess-constitutive laws. These laws, of course, are not inscribed in the nature of things, but are conventional in nature.

As I pointed out earlier, defeasible presumption (DP) and burden of proof are correlative notions.  The defeasible presumption that the accused is innocent until proven guilty places the onus probandi on the prosecution.  Therefore, from the fact that the POI is not itself defeasible in a court of law, it follows that neither is the BOP.  Where the initating BOP lies — the BOP that remains in force and never shifts during the proceedings — is never subject to debate.  It lies on the state in a criminal case and on the plaintiff in a civil case.  If you agree to play the game, then you agree to its constitutive rules.  Since these rules are constitutive of the game, they cannot be rejected on pain of ceasing to play the particular game in question.

3. But in philosophy matters are otherwise. For in philosophy everything is up for grabs, including the nature of philosophical inquiry and the rules of procedure.  (This is why metaphilosophy is not 'outside of' philosophy but a branch of same.)   And so where the BOP lies in a debate between, say, atheists and theists is itself a matter of debate and bitter contention.  Each party seeks to put the BOP on the other, to 'bop' him if you will.  The theist is inclined to say that there is a defeasible presumption in favor of the truth of theism; but of course few atheists will meekly submit to that pronunciamento.  If the theist is right in his presumption, then he doesn't have to do anything except turn aside the atheist's objections: he is under no obligation to argue positively for theism any more than the accused is under an obligation to prove his innocence.

Accused to accuser: "I don't have to prove my innocence; you have to prove my guilt.  I enjoy the presumption of innocence; you bear the burden of proof." 

Theist to atheist:  "I don't have to prove that God exists; you have to prove that God does not exist.  Theism enjoys the presumption of being true; atheism bears the burden of proving that theism is not true." (This assumes that BOP and DP are legitimately deployed within broadly philosophical precincts — which I am denying.)

Note that if the theist invokes the above presumption he needn't be committing the ad ignorantiam fallacy.  He needn't be saying that theism is true because it hasn't been proved to be false.  Surely the following deductive argument is invalid:

No one has ever proved that God does not exist
ergo
God does exist.

Just as the presumption of innocence does not entail that the accused is innocent, the presumption of truth does not entail that the proposition presumed true is true.  So the mere fact that I have the presumption on my side does not amount to an argument that what I am presuming is true.  If I have the presumption on my side, then my dialectical opponent bears the BOP.  That's all.

4. Now we come to my tentative suggestion.  There is no fact of the matter as to where the BOP lies in any dialectical context, legal, philosophical or any other: it is a matter of decision and agreement upon what has been conventionally decided.  In chess, for example, the rules had to be decided and the players have to agree to accept them.  No one thinks that these rules are inscribed in rerum natura.  The same goes for BOP and DP. It had to be decided that in court room discourse and dialectic the accused enjoys the DP and the accuser(s) the BOP.

In philosophical discourse, however, there are no procedural rules regarding DP and BOP that we will all agree on. 

For example, according to Douglas N. Walton, ". . . the basic rule of burden of proof in reasonable dialogue is: He who asserts must prove." (Informal Logic, p. 59) That is clearly false.  If I assert that that you left the door open, there is no need for me to prove my assertion.  A proof is an argument having premises and conclusion.  Surely there is no need to argue for matters evident to sense perception.  In fact, it would be unreasonable to do so.  Or suppose I assert the Law of Noncontradiction.  There is no way I can (non-circularly) prove it.  So I cannot be under any epistemic obligation to prove it.  'Ought' implies 'can.'

And how would this work in a dispute between theist and atheist?  I assert that God exists and you assert that God does not exist.  We both assert.  So we both bear the BOP, and we both enjoy DP?  But then BOP and DP have no application in this area.

I have heard it said that the BOP lies on the one who makes a positive (affirmative) assertion.  But surely both theist and atheist make positive assertions about reality.  'Reality is such that God exists.' 'Reality is such that God does not exist.'   Both propositions are logically affirmative.

Suppose our atheist denies God by saying 'God is an unconscious anthropomorphic projection.'  Logically, that is an affirmative proposition.  Will you conclude that the BOP is on the atheist?

Some say that presumptions are essentially conservative: there is a presumption in favor of the existing and the established  and against the novel, the far-out, and what runs contrary to prevailing opinion.  "If it ain't broke, don't fix it."  Suppose I give the following speech:

There is a presumption in favor of every existing institution, long-standing way of doing things, and well-entrenched and widespread way of belief.  Now the consensus gentium is that God exists.  And so I lay it down that there is a defeasible presumption in favor of theism and that the burden of proof  lies squarely on the shoulders of the atheist.  Theism is doxastically innocent until proven guilty.  The theist need only rebut the atheist's objections; he needn't make a positive case for his side.

Not only would the atheist not accept this declaration, he would be justified in not accepting it, for reasons that are perhaps obvious.  For my declaration is as much up for grabs as anything else in philosophy.  And of course if I make an ad baculum move then I remove myself from philosophy's precincts altogether.  In philosophy the appeal is to reason, never to the stick. 

The situation in philosophy could be likened to the situation in a court of law in which the contending parties are the ones who decide on the rules of procedure, including BOP and DP rules.  Such a trial could not be brought to a conclusion.  That's the way it is in philosophy.  Every procedural rule and methodological maxim is further fodder for philosophical Forschung. (Sorry, couldn't resist the alliteration.)

My tentative conclusion is as follows.  In philosophy no good purpose is served by claims that the BOP lies on one side or the other of a dispute, or that there is a DP in favor of this thesis but not in favor of that one. For there is no fact of the matter as to where the BOP lies.  BOP considerations are usefully deployed only in dialectical situations in which there is an antecedent conventional agreement on the rules of procedure, rules  that constitute the dialectical 'game' in question, and  that are agreed upon by the players of the game and never contested by them while playing it.

Two Putative Counterexamples to My Burden-of-Proof Thesis

A reader presents two putative counterexamples to my claim that burden-of-proof considerations have no useful role to play in philosophy:

I agree that BOP’s in the legal sense don’t exist in philosophical argument, but there seems to be something like a BOP in certain kinds of philosophical debate. I’ll give you two examples and let you tell me what you think. (1) A candidate appears before his committee to defend his dissertation. Depending on the topic and the committee, the candidate knows (and he is told) that he has a significant BOP. His dissertation can be rejected if an examiner does not believe that the work is rigorous and credible enough. The candidate needs to persuade all his examiners that his dissertation is good enough or he will be an unsuccessful candidate. (2) A young Ph.D. wants to publish his dissertation with a top press like OUP. He knows the editor of that press (and his referees)  have very high standards respecting clarity and rigor and substance. The young man has a difficult BOP in persuading OUP to accept his work.
I would deny that in these dialectical situations there is philosophical debate strictly speaking.  In philosophical debate assertions are tested and either proven or disproven.  It is about the probing of propositions, not of persons.  But in the dissertation defense the candidate himself is being tested as to his competence and must prove himself.  Or at least that is what dissertation defenses were before they became formalities.
 
Similarly in the publication case.  The person submitting his work to a press is not entering into a debate with the referees of the press about certain philosophical claims which he must establish to get published; he is having the quality of his work evaluated.  After all, he doesn't have to persuade the referees that the claims in his book are true, but only that they meet a certain professional standard of workmanship.  Both the dissertation defender and the submitter to a prestigious press can 'win' without persuading their respective audiences of the truth of philosophical assertions; but in a genuine philosophical debate, the proponent of a philosophical thesis cannot be said to have won unless he has succeeded in persuading his audience.