Wednesday, February 5, 2014

Lesson 3B: Burden of Proof, Premise Acceptability, Unacceptability, and Questionability

Burden of Proof
One thing we can look at to evaluate an argument's strength is who should bear the burden of proof.  In simple terms, burden of proof refers to whether an intended audience will accept a claim without further support.  If an audience will accept a claim without further support then the any opponent to the claim must provide evidence against the claim (i.e., the burden of proof falls on the challenger).  If an audience doesn't accept the claim without further support, then it is up to the arguer to provide additional support for the claim (that the audience will accept); in other words, the burden of proof falls on the arguer.  

Lets take a step back: Recall that arguments can be decomposed into premises and conclusion(s).  A burden of proof can concern the premises or the conclusion, however, lets first focus on the concept as it applies to conclusions.

2 Heuristics for Burden of Proof
When we evaluate burden of proof, we can apply 2 heuristics
Heuristic 1:  Will the intended (specific) audience accept the claim without further support?  If yes, then the burden falls on the opponents to the claim.  If no, then the burden falls on the arguer.

Heuristic 2 (better):  Would a universal audience (i.e., a group of reasonable people) accept the claim without further support? This is a much better standard of burden of proof for constructing your own arguments because usually we aren't trying to convince people who already agree with us on issues, we're trying to convince a general audience.


When we evaluate an argument for burden of proof with the second heuristic we are essentially asking if its conclusion is something a reasonable person would accept (i.e., universal audience).  If the assertion is reasonable, then the opponent bears the burden of proof to show that we should not accept the assertion. If the assertion is unreasonable, then the arguer bears the burden of proof to show (with further supporting premises) why we ought to accept the particular assertion.  

When the arguer's conclusion isn't reasonable (i.e., when the burden of proof falls upon the arguer's conclusion), an argument must be made!  That is, he's now going to have to support his conclusion with premises (i.e., reasons and evidence).  If, in turn, any of the premises are considered unreasonable, then they too will have to be backed up with further premises.  That is, he will also bear the burden of proof to support those premises until he arrives at support that the audience does accept.

Now we can give a formal definition:  A burden of proof refers to which party (arguer or challenger) has the obligation to defend their position.  It speaks to reasonableness of an assertion (be it a conclusion or a premise); the person who opposes whatever is considered reasonable bears the burden of proof--that is, it's up to them to convince us (through argument) that the default position is unreasonable or incorrect.  Without a supporting argument, we have no good reason to take their point of view seriously.

It's important to note that simply because a position bears the burden of proof it doesn't follow that it is false. Burden of proof just tells us who has to provide evidence for their position. 

Lets look at a few examples to illustrate:
When people deny that the moon landing happened, the burden of proof is on them.  They are taking a position against all experts and mountains of testimonial and physical evidence.  The burden falls upon them to show why we should reject the reasonable position of thinking people landed on the moon.  The reasonable position is that people landed on the moon; to assume otherwise would require further argument.

When people say that the earth is only 6 000 years old, the burden of proof falls upon them.  It's up to them to show why multiple converging lines of evidence are mistaken in their implications and why the theory upon which modern geology and biology are founded is incorrect.  It's reasonable to think that virtually all geologists are well qualified to determine what theories and evidence do or do not apply to to the age of the earth.  To assume a claim that implies that virtually all geologists are wrong requires further argument than mere assertion.

One last note on burdens of proof (laaaaaaaa!):
Historically, burdens of proof can shift.  So, what was a reasonable assumption a few hundred years ago might be unreasonable today.  We see this with social assumptions.  For example, it wasn't too long ago that it was reasonable (for men) to assume that women weren't capable of math and science.  Someone (back then) assuming the opposite would bear the burden of proof.  Today, that burden of proof has shifted.  

Economics is one area where the burden of proof is shifting. It used to be the common assumption that humans are (classically) rational--always seeking to maximize personal interest along the lines of classical mathematical rules. Behavioural economics, interdisciplinary psycho-economics, and socio-economic theory are starting to show these assumptions are wrong.  Giving this mounting empirical evidence, the burden of proof is shifting concerning economic models built upon the assumption of (classically) rational agents.

Notice that when burdens of proof shift, it often has to do with accumulation of evidence (and reasons).  So, maybe in the future we will discover mountains of evidence that the moon landing was a hoax and that the earth is 6000 years old.  If this happens the burden of proof will shift.

Argument Jiu Jitsu
When constructing a strong argument, whenever possible, try keep the burden of proof on your opponent.  Hai-ya! 


Premise/Evidence Acceptability
When it comes to value-based arguments (e.g., political, moral, and religious) we will often not be able to achieve 100% certainty of truth of the premises.  Even something as intuitively obvious like "it's wrong to kill innocent people" will have counter-examples.  However, simply because a premise cannot be 100% true in all cases, it doesn't necessarily mean that we should reject it or that the argument of which it is a part is poor.  Instead, it means we need to be subtle in our evaluations and consider carefully what the logical consequences are of accepting certain premises.

Recall from our previous discussion of premise acceptability that premises/evidence need to meet general two standards:  (1) would the intended audience accept the claims without further support? (i.e., do the premises take into account the audiences "cluster" of beliefs and values) and (2) are the claims acceptable to a "reasonable" universal audience.

Acceptability has much to do with burden of proof.  From the perspectives of both (1) and (2) we need to ask: (3) would these claims be accepted without anyone asking for more evidence/support?  And (4) is there no available information or evidence that we know of that contradicts the claims?  If the answer is "yes" to both, then the premise is acceptable.  If not, then it isn't, and the burden to provide further support for that premise rests upon the person making the argument.   An acceptable premise is one that passes both the intended audience and the reasonable universal audience test.

Questionable vs Unacceptable  Going back to the reasonable universal audience test, if the answer is "no", then we have two possible ways to proceed: In the one case we will say the premise is "questionable" and in the second we'll say it is "unacceptable".   

Evidence/premises are questionable when (a) they fail the "reasonableness" test but we still haven't come up with any direct contradicting claims or (b) we just don't have any knowledge either way on the topic in regards to what a general audience would accept or (c) the wording of a premise is too vague to evaluate.  Very few of us are experts on everything. (Despite what some people might think!).

When you say a premise is "questionable" you need to also include in your evaluation what sort of evidence/additional support the arguer would have to support for their premise to be true.  Then google it!  

Lets look at some examples: Suppose I want to claim that it's an affront to the Olympic spirit that wrestling be removed from the Olympics.  We might point out that the phrase "affront the the Olympic spirit" is quite vague and could be variously interpreted.  So, in our evaluation of the acceptability we might say that the claim is questionable because its meaning is vague.

However, at this point we wouldn't yet be able to say that claim is unacceptable.  An unacceptable claim is one for which there is known evidence that directly contradicts the claim.  Since, in the wrestling case there isn't obvious evidence against the claim (because we're not quite sure exactly what it means), it is not unacceptable, merely questionable.  From the context of the argument we might apply the principle of charity and try to ascribe a reasonable meaning to the phrase. 

The evaluation of "questionable" could also arise where we just don't know much about a topic.  Consider an argument that was commonly heard in the Food Stamp funding debate.  

(P1)  Giving people food stamps removes the incentive to find work and leads to chronic unemployment. 
(C)  Therefore, we restrict or defund the Food Stamp program.

(P1) on its face seems intuitively plausible.  If people are just going to be handed something, why work?  The fact is, however, we aren't sure, so we say the premise is questionable.  

Since we've said it's questionable we need to also specify what sort of evidence or support would be needed for it to be acceptable.  This might be government data on un/employment rates of people on food stamps that shows people on food stamps have high unemployment rates and continue to be unemployed while on food stamps. 

Lets google and find out:  
It turns out that children, the elderly and disabled—i.e., people who, normatively speaking, we don’t expect to fully participate in the workforce—account for 84% of SNAP recipients.  Also, contrary to what the premise needs for support, 58% and 62% of SNAP households with an able-bodied adult work (no children/children) and 82% and 87% are employed within a year. 

This data doesn't give the premise the required support and so we say it is unacceptable and this particular argument against the Food Stamp program fails.If I were to claim that the moon is made of cheese, this claim would be unacceptable since there is known evidence that directly contradicts the claim.

The difference between a questionable and an unacceptable claim is that with the former, it fails the reasonableness test because we don't have enough information (maybe it's too vague or we don't know enough about the topic); and with the latter there is known evidence that contracts the claim that a reasonable audience would be aware of.

The Nitty Gritty:  How Do We Know What a Reasonable Audience Will Accept?
For the most part this is an element of subjectivity here but there are main 2 guidelines we can begin with to determine if a reasonable audience would accept a claim: (A) The claim doesn't contradict any of the other claims made in the argument and (B) the claim could be defended in front of an audience comprised of a broad cross-section of society.  Of course, this still doesn't give us any mathematically precise formula for determining reasonableness but it a start.  In addition, here are couple more heuristics we can use to determine acceptability...

Acceptable By Definition or Self-Evidently Acceptable
Some premises are definitions.  Often, (but not always) definitions are considered self-evident or true by definition.  For example, a triangle is a three-sided figure or a bachelor is an unmarried male.  You can't argue with that.  Ain't nobody got time for that!  For definitions, the litmus test is what a community of language-users would accept as a definition for a term.

We can also have claims that are self-evident because they are logical truths, like "a thing cannot both exist and not exist at the same time."

Self-evident claims can also pertain to the moral realm (unless your audience is philosophers!).  Statements like, "causing unnecessary suffering is bad" or "killing innocent people is bad" are considered self-evident to a reasonable general audience.

Acceptable as a Factual Statement Reporting an Observation or as a Statement of Eye-Witness Testimony
Unless we are provided with some reason not to, we accept people's testimony about what happened to them or what they observed.  If someone said "it's sunny outside yesterday," you have no reason not to accept the claim. Also, if I told you that I was going to the store to get myself a cold pop, you should accept my claim at face value.

Of course, if I have a reputation of being a big fat liar, then you'd have reason to be skeptical of my claims.  Also, if what I said happened to contradict something else I'd said, then you would also have reason to question the acceptability of my claim.  But barring such situations, we take speaker observations and testimony at face value.

Acceptable by Common Knowledge or Assent
We have to be careful with this one because it can lead us to accept things uncritically that we probably shouldn't.   "Common knowledge" can be divided into 2 categories:  factual claims and value claims.  A factual claim would be something like, "the earth is a spheroid" or "Obama is the current president of the USA."  A value claim or value judgment would be something like, "it's wrong to hit children" or "we shouldn't allow people to starve."

So, where does acceptability fit into this?  Although we said previously that acceptability depends largely on what a reasonable member of a universal audience would accept, there are exceptions.  Concerning factual claims, if the intended audience has specialized knowledge (doctors, scientists, etc...) then it's OK to evaluate the claim in relation to the knowledge base we'd expect that group to have.

We might reply, but wait! What happens if the knowledge isn't known by every member of that audience?  In such cases, we can make assumptions about what factual knowledge we'd reasonably expect the members of a specific expert audience to have.

In all this talk of specific audiences, lets not lose sight of the "common knowledge by a universal audience" aspect of this criteria.  Just because some knowledge might be particular to a field of study or expertise, doesn't mean that there isn't knowledge that we can reasonably expect Joe Schmo to know.   Stuff like, "the third Batman movie was awful" or "grass is green" or "Las Vegas is the entertainment capitol of the world" are all things that we'd expect a general (North American) audience to know and so we can accept them at face value.   Similarly "Uzbekistan was part of the former USSR" is something we'd reasonably expect every general audience outside of the USA to know :)

Acceptable Because it is Defended in a Reasonable Sub-Argument
In Mill's proof of utilitarianism he makes the sub-claim that the general happiness is good to all humans.  This is on its face is not a claim that we'd expect a universal audience to accept.  However, Mill, knowing what a general audience might not accept, provides a supporting argument working from our particular desire for our own happiness to the more general claim.  

Since he supports his sub-claim with a reasonable argument we can now accept it.  (And consequentially turn our critical thinking toward the supporting sub-premises.)

When evaluating for premise acceptability, we can do the same with any sub-claim.  It it doesn't seem reasonable we can see if it is supported by a sub-argument.  If it is, and that sub-argument is reasonable, then we can accept the sub-claim.

Acceptable on the Authoritar of the Arguer or an Expert
We can broadly divide this criteria into two types:  uncontroversial claims made by an arguer and claims made by an expert.

In the first class these are claims about relatively uncontroversial things that the arguer might know about.  For example, I might say that the University of Houston has a good philosophy graduate program.  Because I've been there and you haven't, you have no grounds to doubt my claim and since it isn't particularly contentious, it should be viewed as acceptable.

In the second class we have claims made by experts.   This is known as an "appeal to authority".  This is when the arguer supports a claim by appealing to the expert knowledge of a person, institution, or source.  

A quick note here, the best appeals to authority are appeals to the consensus opinion of a community of experts.  Appeal to a single expert doesn't carry much weight, especially in controversial topics.  The opinion could easily be an outlier.

Conditions of Unacceptability
Unacceptable because of an Inconsistency
We might label a claim as unacceptable because it is inconsistent with other claims the same arguer has made.  For example, in alt-med we often see arguments stating that the flu vaccine shouldn't be used because its efficacy can sometimes be as low as 45%.  However, the northern Andean magic rainbow-berry or acupuncture they propose instead has no reported efficacy.  

So, if the argument is that we should reject a treatment because of low efficacy, the same should apply to their conclusion.

We also hear that we shouldn't take manufactured (i.e., "unnatural) drugs because big-pharma's just trying to sell you stuff to make money, then in the same breath they will try to sell you the latest all-natural (!) miracle cure...and not for free either!

To be sure, inconsistency doesn't mean the conclusion is false, it only means that the argument for the conclusion is poor and we need to either reject the premise(s) or the conclusion (or both) because both can't be true.  Sometimes people can hold the right views (conclusions) for the wrong reasons or as a matter of dumb luck, not because they arrived at them through good argument.

Unacceptable because of Begging the Question
The current use of "begging the question" meaning "raises the question" is something that irks philosophers to no end.  The original meaning of the phrase is "circular reasoning."  In other words, in your argument, you assume to be true the very thing you are trying to prove.

The classic example comes from an unsophisticated religious argument for the truth of the contents of the Bible.  A caricature of the argument goes like this:  How do you know what's in the Bible is true?  'Cuz it's the word of God.  How do you know it's the word of God? 'Cuz it says so in the Bible.

Notice that for the argument to work you have to assume the very thing the arguer tries to prove:  that the contents of the Bible are true.

Unacceptable because of Language Problems
We can call a premise unacceptable if it has one or more of the language problems we encountered on the section on definitions.  In other words, if the language of the premise is overly vague or suffers from semantic and/or syntactic ambiguity, we might say it's unacceptable (if context can't reasonably sort it out).

Suppose I claim that "I've never been seriously sick since I started taking Tibetan Booga-Booga Bush capsules.   We can't accept this claim because "seriously sick" is too vague.  For how long and for what intensity do I have to be sick to be "seriously sick".  Do I need to be hospitalized or just miss work?  Or maybe just miss my work out.   It's not clear from the phrase so we'd say the premise is questionable or unacceptable depending on the severity of the vagueness.


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