10. ORIGINS OF CERTAINTY (2)

Now that we know why evidence imparts certainty to a claim, we need to know how evidence matters to a claim. 

What makes evidence matter, as Stephen Toulmin tells us, is its warrant.¹  Let’s define warrant as a rule which dictates what is allowed as evidence and how compelling it is.

Let’s look at a few examples of warrants.

Suppose that the Mr. Slaughter claims he could not have murdered Mr.  Corpus in London because Mr. Slaughter was in Gravesend at the time.  Here the accused appeals to the warrant that no man can be in two places at once.  This warrant makes Mr. Slaughter’s presence in Gravesend compelling evidence of his innocence.

If Mr. Fraile says he is sick, why does it matter if his temperature is 99 degrees?  It matters because of the rule that if someone’s temperature is above 98.6 degrees, he is sick.  If Mr. Fraile says he cannot go to work today, his fever is likely to persuade his boss.

Reverting to the Dover Restaurants problem, my warrant could be that if the owner of a restaurant cannot be bothered to maintain his building properly, he likely cannot be bothered to serve good food, either.  As warrants go, this warrant does not seem to be as persuasive as Mr. Slaughter’s warrant or the feverish warrant, but that is okay.  In a pinch, it could give me some quick way to make up my mind.

In all three examples, the warrant states or implies what sort of evidence must be introduced in order to confirm the claim.                 

How does warrant relate to certainty? 

I do not have a complete answer to this question, nor is it likely available, but we may make a start here by distinguishing important types of warrants which confer different degrees of certainty.²

If we return to the case of Mr. Slaughter, we see that his warrant confers necessity upon his innocence, since his warrant cannot conceivably be violated.  This kind of warrant is called a metaphysical warrant.  Similar warrants are A statement may not be false and true at the same time in the same sense; killing for no reason is morally right; whatever is, is; and so forth.  It is characteristic of metaphysical warrants that violating them drives us to either incoherence or madness.    

In Mr. Fraile’s case, the feverish warrant is a kind of physical necessity.  Physical necessities “are ultimate facts, which we take on the evidence of experience, without being able to give their final account.”³  Natural necessities are squishier than metaphysical warrants.  For instance, water may boil at 212º F for most people, but the inhabitants of the Mile High City know that a full statement of the facts must include air pressure to explain for when water boils.  Warrants involving natural necessities are not as conclusive as metaphysical warrants, but they are still sturdy.

Finally, we have moral warrants.  A moral warrant relies upon the moral character of the person involved.  This kind of warrant demonstrates in range of certitude exactly that range occupied by moral character.  

At one end of the range, Rickaby observes that “it is a sheer impossibility that historians should be deceiving us, when they narrate certain substantial events in the lives of Alexander the Great, Julius Caesar, and Charlemagne.”⁴  He can say this for a number of compelling reasons—the sheer abundance of evidence from the earliest times on, the consensus of the learned, the stigma (once) attached to mendacity among historians and so forth.

At the other end of the range, I would not ask a used car salesman to tell me the value of a car on his lot and pay that price with the conscience of a man who has done all he could to secure a fair deal; the salesman has too many reasons to inflate the price. 

In the Dover Restaurants problem, my warrant is a moral warrant.  The kind of person who keeps his restaurant looking spic and span is in my experience more likely to offer a decently and hygienically prepared meal, but I could not swear by it.  This illustrates why the moral warrant is tricky to apply.

In conclusion, if evidence is what leads us to the truth, warrant is what confirms the viability and weight of the evidence.  Warrants are not equally authoritative, so we have to pay attention to the type of warrant being used when we evaluate an argument.

ENDNOTES

1.  I rely throughout on the Toulmin Model Argument, as the perceptive reader will note.  For details, see Stephen Toulmin, Richard Rieke, Allan Janik, An Introduction to Reasoning, 2^nd ed. (NY:  MacMillan Publishers, 1984).

2.  The astute reader will note that I am using Rickaby’s discussion of the three kinds of certitude (The First Principles of Knowledge, 4^th ed. [London:  Longmans, Green & Co., 1901], 44) to provide a classification for Toulmin’s otherwise unwieldy concept of warrants.

3.  Rickaby, 57.

4.  Ibid., 58.