Jeffrey on Value of Knowledge

I've been revisiting some classics in the foundations of subjective probability and thought I'd share this opening paragraph from Richard Jeffrey, "Probable Knowledge," p. 227 in Kyburg and Smoker, Studies in Subjective Probability (1980).

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The central problem of epistemology is often taken to be that of explaining how we can know what we do, but the content of this problem changes from age to age with the scope of what we take ourselves to know; and philosophers who are impressed with this flux sometimes set themselves the problem of explaining how we can get along, knowing as little as we do. For knowledge is sure, and there seems to be little we can be sure of outside logic and mathematics and truths related immediately to experience. It is as if there were some propositions--that this paper is white, that two and two are four--on which we have a firm grip, while the rest, including most of the theses of science, as slippery or insubstantial or somehow inaccessible to us. Outside the realm of what we are sure of lies the puzzling region of probable knowledge--puzzling in part because the sense of the noun seems to be cancelled by that of the adjective.
The obvious move is to deny that the notion of knowledge has the importance generally attributed to it, and try to make the concept of belief do the work that philosophers have generally assigned the grander concept. I shall argue that this is the right move.
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I would say *justified* belief rather than belief simpliciter, but the point is well-taken-by-me. However, the passage seems a bit obscure in one respect.

The obscure-to-me part is that Jeffrey seems to be instantiating this argument pattern.

(JA1) Knowledge is rare, thus knowledge is not valuable.

This seems quite odd since value usually varies in direct proportion to rarity: "scarcity begets value". Yet this interpretation is hard to avoid. Consider the sentences of the paragraph sequentially. S1 is a statement about the history and sociology of epistemology and poses the following question.

(JQ1) How do we get along, knowing as little as we do.

S2 and S3 defend the presupposition of the rarity of knowledge in (JQ1), i.e. the Rarity Thesis.

(RT) Knowledge is rare (among humans generally).

Then S4 coins a new technical term "probable knowledge" which I assume comes to this.

(JPK) Epistemic item k is an instance of probable knowledge for S at t iff at t S knows p, but S isn't sure that p (or perhaps has no *right* to be sure or has no *grounds* for surety or what have you).

But then the very next "move" is to assert the Knowledge-ain't-all-it's-cracked-up-to-be Thesis.

(KACTB) Knowledge doesn't have the value traditionally attributed to it.

Now I heartily endorse (KACTB) but (JA1) doesn't seem to be the right way to get there at first blush.

However, I think there's a hint in (JQ1). Presumably, whatever "getting along" entails, it entails using items with some kind of positive epistemic status (to use Chisholm's phrase) to guide our decisions. This has traditionally been attributed to knowledge (see my post here concerning Chisholm on knowledge, the right to be sure, and action-guiding evidence).

If knowledge *did* play this important role of being that-which-guides-our-decisions, then that would surely confer a good deal of value upon it. However, precisely what Jeffrey will endorse, of course, is Bishop Butler's Thesis.

(BBT) Probability is the very guide of life.

If my reconstruction is right, then the idea is this:

Argument A

1. Knowledge has its traditional degree of value only if it's the very guide of life (in the sense that sub-known items are *not*).

2. But knowledge is *not* the very guide of life (in the sense specified in 1).

3. Thus, it is not the case that knowledge has its traditional degree of knowledge.

So we've got a valid argument and I take (BBT) to be secure--in some precisification at least--and so 2. is true. Thus 1 is the premise to focus on. The best reason I can think of to deny 1. would be be some form of the Knowledge Maximality Thesis.

(KMT) Knowledge entails a maximal, or near maximal, degree of some positive epistemic status.

This would be true if, for instance, knowledge entailed certainty (which I take it it does not) or the right to be sure (see post link above).

But even then as long as not *all* of the value traditionally attributed to knowledge was explained by (KMT) and *some* were derived from exclusive-action-guidance 1 would still be true. It's degree of truth would depend on the degree to which the value traditionally ascribed to knowledge was derived from this function. The following thesis, at least, seems safe:

(TD1) To the extent that the value of knowledge was derived from exclusive-action-guidance, to that very extent (BBT)--suitably understood--threatens the value of knowledge.

So if we had the following premise

(P1) A lot of the value of knowledge was derived from it's supposedly being exclusively action guideing.

then we'd have the following conclusion via (TD1) and (P1).

(C1) A lot of the value of knowledge is threatened by (BBT).

Now clearly (KMT) mitigates (C1), but--in addition to the Chisholm reference above--the literature on induction and inductive acceptance (the portion which doesn't attend to probability kinematics) is replete with something akin to the the Knowledge Is the Very Guide of Life Thesis.

(KGLT) Knowlege is the very guide of life.

There are two forms of (KGLT) I see quite often in the literature on induction.

(KGLTa) Knowledge is the evidence upon which we conditionalize.

(KGLTb) The data upon which (ampliative) inductive principles operate are those known via empirical observation.

The probabilist (radical or not who accepts (BBT)) will reject both theses.

So it seems that probabilism constitutes one route to a value-shift in epistemology, a transference of some of the value--plausibly a considerable quantity--of knowledge to belief or justified belief.