Tuesday, 3 April 2012

Outline of Clark's "Knowledge and Grounds"


Michael Clark argues that the necessary and sufficient conditions for S knowing that p are:
(1) p is true,
(2) S believes that p,
(3) S is justified in believing that p, and
(4) S’s belief that p is fully grounded.


STEP 1: Clark observes that Gettier’s examples are stronger than they need to be since he presents cases in which an agent’s grounds for a belief deductively entail the proposition believed, whereas there may also be Gettier-type cases involving non-deductive grounds.

Example: Suppose that Smith forms the true belief that Jones owns a Ford based on the testimony of Brown, who is typically reliable, but who (on the present occasion) has mixed up Jones with someone else. Although Smith’s belief (based on Brown’s testimony) is true and justified, it fails to constitute knowledge because it rests on false grounds. Insofar as Brown’s testimony constitutes non-deductive grounds for believing that Jones owns a Ford, this is a Gettier-style example involving non-deductive grounds.

Upshots: (i) Insofar as Brown’s testimony constitutes non-deductive grounds for Smith’s belief, Gettier-style examples are effective within a non-deductive context. (ii) S knows that p only if her belief that p is not based on false grounds.

STEP 2: Clark argues that adding the fourth condition that an agent’s belief be based on true grounds is still insufficient for knowledge.

Example: Suppose that Smith forms the true belief that Jones owns a Ford based on the testimony of Brown, who is typically reliable, but who (on the present occasion) is simply making up a claim that (unknown to Brown) happens to be true. Although Smith’s belief is true, justified, and rests on true grounds (i.e., Brown’s claim that Jones owns a Ford), it still fails to constitute knowledge. Thus, we have a Gettier-style example involving true grounds.

Upshot: Although Smith’s belief is based on true grounds, Smith lacks knowledge because the grounds on which he accepts these true grounds, viz. that Brown knows them, are false.

STEP 3: Clark claims that if we keep inquiring about someone’s grounds for accepting certain grounds, and the grounds for accepting those grounds, and so on, we eventually come to a place where it would be inappropriate to ask for further grounds.

Example: A series of questions posed to Smith about why he believes Jones owns a Ford will eventually culminate in an answer, which we would deem out of order to question further.

Upshot: There is always some finite list of grounds that can be offered for a belief.

STEP 4: Clark posits that if one of the grounds in the chain of supporting grounds for a certain belief is false, then that belief fails to constitute knowledge.

Example: If any of the beliefs in the chain of Smith’s grounds for believing Jones owns a Ford are false, we may deny that Smith has knowledge. If all the beliefs in the chain are true, then Smith’s belief that Jones owns a Ford is fully grounded.

Upshot: Being fully grounded is a necessary condition for a belief to constitute knowledge.


Clark concludes that if we add the requirement that S’s belief that p be fully grounded to the requirement that p be true, S believe that p, and S’s belief that p be justified, we arrive at conditions that are jointly sufficient for knowledge.


1. Is Clark’s analysis of knowledge a successful response to Gettier-style counterexamples? If not, can you recommend any changes that would improve Clark's account?


Na'Quelle D. said...

As far as I understand Clark's purpose in setting out to write his response to Gettier, his argument appears to achieve the exact opposite effect he was going for. It seems like he was attempting to offer a new condition to the proposed models of knowledge to both satisfy the objections raised by Gettier and to also establish a wholly satisfactory outline of the necessary and sufficient conditions for knowledge. However, all he ends up doing is strengthening Gettier's argument.

Yes, he adds the condition that, in addition to p being true, s believing that p is true, s being justified in believing that p is true, s's belief in p must be fully grounded. However, he then goes on to offer us an example in which all of those conditions are met but that still does not amount to what I would consider knowledge. If Clark had simply argued that Gettier's counterexamples were stronger than they needed to be, his paper would be much stronger (and he wouldn't end up contradicting himself later).

Russell Buehler said...

As phrased, no for the reasons given in class. It may be possible to save Clark's general idea by reinterpreting grounds more along the lines of assumptions (this is not in line, of course, with the conception Clark presents in his example). To see this, consider again Clark's example; instead of his question and answer, the chain would look more like:

(1) Jones owns a Ford.
(2) What is your grounds for believing that?
(3) Brown told me Jones owns a Ford.
(4) What is your grounds for believing that?
(5) I assume Brown knew that Jones owns a Ford.

Even to me, this response seems a bit cagey and what does / doesn't count as a grounds needs a great deal of explication. That said, it is possible to cash out the failure of Clark's example by saying that `Brown is usually reliable' simply isn't a sufficient grounds for knowledge, and so it should have failed. I haven't spent a great deal of time with my revised example, but I think it does, in fact, avoid at least the problems Clark's did.

Taylor fficth said...

I agree with Na'Quelle and Russ that Clark doesn't effectively rebut Gettier. In fact, as we discussed in class, he seems to create a stronger Gettier example, since he creates a string of properly grounded propositions that nevertheless don't lead to knowledge.
Having read the Goldman piece on causality, I can see that this idea might be closer to what Clark was getting at with his idea of being fully grounded. I have some reservations about the causality argument, but I'll save those for a post on Goldman.

Andrew Cely said...

I'm in agreement with the rest of the comments above, as we discussed in class how Clark's arguments only seem to fuel the Gettier counter-examples. Simply because someone is 'reliable' in terms of how often they tell the truth or are correct discussing certain matters does not mean that is an accurate foundation for knowledge, at least in my own personal definition. Sure, you have the knowledge that they are most often reliable, but that does not mean that you know for certain that the grounds for your friend's reliability are completely true.