Acceptable Premises

PART I

ACCEPTABILITY

Dialectical and Epistemological Considerations

1

Why do We Need a Theory of Acceptability?

When, if ever, is a premise – indeed a statement in general – acceptable? That is the central question of this book. Therefore, this is a normative investigation. This point needs to be underlined, as the very word “acceptability” contains an ambiguity. A statement’s acceptability may mean its prospects for being accepted by a certain audience. This is not our meaning. We are not interested in the marketability of a statement but in whether the statement should be accepted. Is acceptance rationally justified for a particular audience? However, there are two preliminary issues we must address. Why is this book needed at all? Is there no simple, straightforward, and adequate answer available? The simplest way to address this question is to look at certain simple and straightforward answers and see that they either do not answer the question correctly or are fraught with problems. But first we should clarify what it means to accept a statement, and so by implication what “acceptability” means.

1.1 ACCEPTANCE – A BASIC DEFINITION

In (1992), L. Jonathan Cohen contrasts these two concepts: To believe a proposition that p is to be disposed to feel that p is true and that not-p is false, whether or not one is prepared to take that p as a premise for further belief or action. To accept that p is to take that p as a premise “for deciding what to do or think in a particular context, whether or not one feels it to be true that p” (1992, p. 4). Accepting a statement as a premise does not mean assuming it just for the sake of argument but unconditionally or categorically. We might talk of conditional acceptance or define assumption as conditional acceptance. But doing so would be confusing. Our ultimate interest is normative. We are concerned not just with what accepting that p means but with the conditions under which acceptance is justifiable. Such normative questions do not arise for premises taken conditionally. We can assume just about any statement we want.

   Acceptance then is unconditional in the sense that accepting a statement means taking it categorically as a premise. But is acceptance categorical, unconditional in the further sense that proper, normatively correct acceptance is irrevocable? Are only statements that we could see not to be subject or open to defeat be properly acceptable? We should specifically address this major philosophical issue at the outset of our inquiry. On the one hand, there are intuitions indicating that we may quite properly accept a statement at one point in time fully acknowledging the possibility that at some future time we shall withdraw that acceptance in the light of further evidence. Acceptance, then, is not irrevocable commitment. We are not confronted with counterevidence now, else we could not accept the statement. But we may admit the possibility of such evidence. This is not to say that indefeasible statements are not accepted or that one never takes any statements he or she accepts as necessary or indefeasibly true. This also may happen. But, on this view, indefeasibility is not a necessary condition for acceptance.

   On the other hand, there is a whole philosophical tradition that would see defeasibility as a bar to acceptance. In particular, indefeasibility is a necessary condition for the acceptability of basic premises. This is classical foundationalism, a position that we must address. Is certainty then a necessary condition for acceptability? This question raises the basic epistemological assumptions and approach of our inquiry. Our answer will determine the subsequent direction of our investigation and the extent to which it is philosophically undergirded. We turn directly to this issue in the next section.

1.2 ACCEPTABILITY, CERTAINTY, AND EPISTEMIC DUTY

That certainty is a sufficient condition for acceptability seems straightforward. If I am certain of a proposition p, what more reason could I need to take p as a premise for further deliberation or action? But what are we to say of the claim that certainty is a necessary condition for acceptability? On a foundationalist picture of knowledge, some beliefs will be basic, not accepted on the basis of propositions presented as evidence for them. Other beliefs will be accepted on the basis of propositional evidence. This evidence will consist either of basic beliefs or of beliefs accepted on the basis of yet further propositional evidence. There are, however, no infinite regresses of support. Any chain of propositions A₁, A₂, where A₁ is accepted on the basis of A₂, A₂ on A₃, A₃ on A₄,..., will be finitely long and will ultimately end in basic propositions. This grounding relation also will not be circular. A₄ will not be accepted on the basis of A₁, for example.

   For such a structure of beliefs to be knowledge, the basic propositions or beliefs must satisfy certain conditions. Some beliefs may typically be basic because it is hard to see how anyone would want evidence to support them or what propositions one would offer in their support. I seem to see a truck hurtling down the highway toward me or I seem to hear thunder (am appeared to thunderously). What evidence in the form of propositions would be needed or could be offered for such beliefs? Other beliefs are basic not because propositional evidence could not be given for them but because typically it would not be needed. I can just see that some simple a priori truths are true. Once I understand the concepts involved, do I need evidence for the laws of identity, noncontradiction, or excluded middle?

   But not every proposition taken as basic need be properly basic. According to Plantinga, a belief is properly basic for me if it is basic for me, and also meets some other condition C, differing choices for C leading to different varieties of foundationalism (1993a, p. 70). Although classical foundationalists may themselves differ on the exact formulation of condition C, a belief satisfying C will be certain. For Descartes, C will be the condition that a belief be sufficiently clear and distinct. For Locke, “a belief is properly basic for me only if it is either self-evident or appropriately about my own immediate experience” (Plantinga, 1993a, p. 71). But in either case, such beliefs will be certain. For Descartes, the only other beliefs that are acceptable besides basic beliefs are those deductively entailed by basic beliefs. For Locke, if a belief follows deductively or is sufficiently supported inductively ultimately by basic beliefs, it is acceptable. Classical foundationalism thus lends the weight of its influence to the view that certainty is a necessary condition for acceptability, at least for basic acceptability.

   What is the rationale for this position? At the beginning of the First Meditation, Descartes says that “reason already convinces me that I should abstain from belief in things which are not entirely certain and indubitable no less carefully than from the belief in those which appear to me to be manifestly false” (1960, p. 75). Reason convinces Descartes of this because his goal is to achieve at least some “firm and constant knowledge in the sciences” (1960, p. 75). If that is one’s goal, then one should abstain from accepting propositions that are less than certain, lest they render one’s scientific opinions questionable.

   In the Fourth Meditation, however, Descartes apparently goes further. We should unconditionally refrain from accepting what is not understood clearly and distinctly. Not to refrain is to use one’s free will improperly, which may give assent only to what is seen with sufficient clarity and distinctness. (Compare Descartes 1960, p. 115.) Otherwise, one risks falling into error, misusing the will. It is our epistemic duty then to avoid error and this requires accepting nothing except what is seen clearly and distinctly.

   John Locke also enunciates this same theme of epistemic duty. However, while Descartes enjoins accepting nothing but what is perceived with sufficient clarity and distinctness, Locke endorses accepting nothing except on good reason. “Faith is nothing but a firm assent of the mind: which if it be regulated, as is our duty, cannot be afforded to anything, but upon good reason” (quoted in Plantinga 1993a, p. 13, italics added). For Locke, certainty is a necessary condition for basic acceptability, for the acceptability of basic premises.¹ To simply accept a proposition that is not certain, without adequate reason, would violate epistemic duty for Locke.

   What are we to say to the view that the only basically acceptable propositions, acceptable in themselves without argument, are those that are certain? What propositions are certain? Clearly, besides truths of reason they are propositions about our experience in the sense of how we are appeared to or about the immediate contents of our minds. Should I perceive a tree in front of me, the proposition that there is a tree in front of me is not certain, for this may be a skillful illusion. What is certain is that I am now appeared to treely. Truths of formal logic and mathematics, together with semantic truths, statements true by virtue of the very meaning of the nonlogical constants they contain, are certain. These are the traditional truths of reason. But clearly, not every such truth is acceptable as a basic premise. For a mathematical truth may be certain, yet require much ingenuity to show it certain. But surely there are some truths of reason whose status or certainty can be immediately recognized. These propositions are self-evident. What then may we say to the claim that only propositions that concern one’s immediate experience or are self-evident truths of reason, the properly basic propositions of classical foundationalism, are acceptable as basic premises?

   We argue that this view (1) has unacceptable consequences for ordinary deliberation and action; (2) has unacceptable consequences for argumentation; and (3) is neither self-evident in itself nor provided with sufficient argument. Concerning (1), should only propositions concerning one’s immediate experience or stating self-evident truths of reason be basically acceptable, I could not accept that there is a tree in front of me without evidence in the form of propositions supporting that claim. What would that argument be like? Can I show that there is a tree in front of me from propositions about how I am appeared to treely? Is any statement then reporting what we are now perceiving ever acceptable? But if I am looking at the tree in good light, with normal perceptual abilities, what reason have I for doubting that the color, shape, size I perceive are veridical? Is the fact that my senses have been occasionally deceived strong enough reason for doubt here, pace Descartes?

   On this view, I could never accept anyone’s testimony without evidence in the form of argument. Accepting what someone says as to time of day, direction to my destination, indeed answers to just about any question I might ask is not proper. Not only would personal testimony not yield any statements acceptable in themselves, neither would expert opinion nor so-called common knowledge. I cannot accept without evidence my doctor’s diagnosis or commonly acknowledged reports about the past or commonly agreed to moral judgments. None of these statements may I take as basic premises for further deliberation or action. But unless I have reason to think these sources mistaken or deceiving, why should I not accept personal testimony or that of experts or “common knowledge”? If I do not, how could I get around in the world? What would I have to reason from?

   Concerning (2), that this view would have unacceptable consequences for argumentation, it would seem that in attempting to convince others of some claim by argumentation, our stock of basic premises would be even more limited. For if I am genuinely trying to get my audience to accept some claim, the premises of my argument should be statements my audience already accepts. Can I in the course of this argument appeal to a basic premise about my experience? Are such claims certain for both speaker and audience when used as premises in arguments? It may be certain to Descartes that he thinks, but should he offer that proposition as a premise in an argument, it will not be certain to his audience that Descartes thinks. Likewise, it seems that incorrigible propositions are self-evident only to persons who report about their own current perceptions, what each is perceiving right now. But although “The fire seems hot to me now” may be certain for Descartes, should he offer it as a premise, it will not be certain for his audience that the fire feels hot to Descartes. Does this mean that these types of propositions which are certain are available only in arguments with oneself? That would be too hasty a conclusion.

   Descartes could phrase his premise this way: “Consider what you are doing when you entertain this premise. Isn’t it evident that you are now thinking?” If the addressee admits yes, she has admitted that she herself, not Descartes, thinks – a proposition apparently certain to her. Should Descartes say “Look at and feel this. Isn’t it evident that it looks blue and feels hard?” Again, if the addressee admits yes, she has admitted that this looks blue and feels hard to her, not Descartes. In this way, Descartes could build an argument on premises certain for his audience. But there is something very anomalous here. These premises may be certain to the audience, but not to Descartes himself. Should one accept without argument only those propositions that are certain, then Descartes should not accept the basic premises of the very argument he is constructing (even though analogous statements are self-evident to him). But how can Descartes argue sincerely if he does not accept the very premises from which he argues?

   We find the view that the properly basic propositions of classical foundationalism only are acceptable as basic premises is neither itself self-evident nor has it been properly supported by argument. We might think of taking a proposition as a basic premise as taking a risk. The classical foundationalist view then is tantamount to saying that the only acceptable risk is the null risk. Why is it unacceptable to take risks? Certainly that view is not self-evident as an investment strategy, and neither does it appear self-evident as an epistemic strategy. Have classical foundationalists presented compelling arguments for this requirement of certainty? As we noted earlier, Descartes may justify the claim conditionally. If our goal is to identify or reach sure knowledge in the sciences, then we should reject what is less than certain for our basic premises. But what if that is not one’s goal, or not one’s goal in all situations? Why then should one refuse to accept what is not certain?

   To find arguments in Descartes, it seems we must reconstruct them. In (1971), Wellman ascribes two arguments to Descartes that reasoning must go back ultimately to self-evident or indubitable premises, and he rebuts each.²

(1)	Knowledge is distinguished from mere belief by its certainty. Any conclusion based upon premises that could possibly be doubted is itself subject to doubt. Therefore one can claim to know that a conclusion is true only if it is derived from indubitable premises. (Wellman 1971, p. 145)

The problem with this argument, as Wellman points out, is the first premise. Why should we understand knowledge this way? Furthermore, the premise apparently involves a false dilemma. Are certain knowledge and mere belief our only two alternatives? Is not rationally justified belief a third? (Compare Wellman 1971, p. 146.)

(2)	There is always reason to doubt any conclusion based upon premises that are less than indubitable. So since one has reason to doubt such a conclusion, one is rationally unjustified in accepting it. (Wellman 1971, p. 146)

In (1), Wellman accepted the inference but rejected a premise. Here Wellman accepts the premise but rejects the inference. Why, just because there is reason to doubt a conclusion, are we rationally unjustified in accepting it? We would be rationally unjustified in accepting the conclusion unconditionally, but not tentatively (Wellman 1971, pp. 146–47). So the arguments for the classical foundationalist strictures are not sound.

   But we may bring an even more devastating criticism against classical foundationalism. Following Plantinga, we may claim that many forms of this view are self-referentially incoherent. What of the claim C that a statement is acceptable if and only if it is either self-evident, concerns my immediate experience, or is supported ultimately by such statements? Is C itself acceptable according to C? (Compare Plantinga 1993a, p. 85).

   As we have pointed out, if our goal is certain knowledge, then only what is clear and distinct is acceptable. But this leaves it open whether there is not some wider sense of knowledge or justified belief, subject to normative regulation, which need not be certain. Another remark of Descartes is quite suggestive. He feels he cannot overdo his doubt, “since it is not now a question of acting, but only of [meditating and] learning.” (1960, p. 80) Does this mean that when it is a question of acting, accepting noncertain propositions is appropriate besides accepting certain propositions? Descartes does not address this question, but one wonders why he would allude to this distinction if practical contexts did not allow a wider field of acceptance. Hence the classical foundationalist demand for certainty – of our basic premises at least – is not warranted, at least as a general requirement on basic premises. If certainty is not required for acceptability, then what is? What criteria adequately delimit acceptability? We can readily think of a number of initially plausible answers, all ultimately problematic. We consider them in the next section.

1.3 “POPULAR” CRITERIA FOR ACCEPTABILITY

i. A Statement Is Acceptable If and Only If It is True

This is perhaps the simplest and most straightforward answer concerning acceptability. But we can readily see its inadequacy as others have amply shown. Being true is neither necessary nor sufficient for being acceptable. It is not necessary because the preponderance of evidence at one’s disposal might favor some statement which is, in fact, false. That statement would then seem worthy of acceptance. It is not sufficient, for a statement may in fact be true, yet one might possess no evidence for it. Indeed, the preponderance of evidence one possesses might even be against it. In such cases, the statement would not be worthy of acceptance from one’s point of view, even though true.

   Blair raises an interesting objection to the claim that truth is not a necessary condition for statement acceptability in (1986). Some will claim that if statements are properly hedged then we can demand that they be true before accepting them. So, for example, where the preponderance of evidence supports “A is B” we should accept “A is probably B,” unless the evidence actually entails that A is B. Fogelin points out in (1982) that there are two ways to hedge a premise or statement. Besides probabilistic qualifications, we can weaken the statement, replacing “all” by “most,” “usually,” “typically;” “most” by “many” or “some” (1982, p. 46). What may we say to this proposal? Will this hedging transformation always result in a true statement, allowing the critic to demand that only true statements be accepted? I believe the answer is negative for both types of hedging.

   Suppose the preponderance of evidence is for Jones’s guilt. Will I be assured of accepting a true statement if I accept not

(1)

Jones is guilty

but

(2)

Jones is probably guilty?

This move completely misconstrues the function of the modal word. In (2) and statements like it, there is tacit reference to the evidence supporting the claim of Jones’s guilt. The modal word “probably” is really not part of the statement, but serves to make a claim about how strongly the evidence supports that statement. Although the conversational force of “probably” may be to indicate a weaker degree of commitment, literally we have not produced a weaker statement, but the same statement together with a comment on the weight of its supporting evidence.³