There are two ways to understand this request. On the one hand, it is a common intuition about knowledge that whatever it is that we "know" must in fact be true. Hence one might explore the basis of this intuition and the role that truth plays in the philosophical definition of knowledge. On the other hand, "tracking the truth" is a phrase closely associated with the "truth-tracking" theory of knowledge proposed by Robert Nozick. Hence one might explore the genesis and consequences of Nozick's theory. It is this second interpretation of the essay title that I will pursue in this essay.
The traditional definition of knowledge
is the so-called "Tripartite Model" first documented by Plato. The tripartite
definition of knowledge maintains that --
S knows that P iff (1) P is true; and
(2) S believes that P; and
(3) S's belief that P is justified.
This ancient standard captures our intuitions that one cannot properly claim to know something that is in fact not the case, or if one does not believe it to be the case, or if one does not have proper justifying reasons for one's belief that it is the case.
Unfortunately, ever since Plato, the standard model stumbles over just exactly what is meant by "proper justifying reasons" for one's beliefs. The model does not specify this detail. It has been left to the two millennia of epistemologists since Plato to work out just what "proper justifying reasons" really means. And it is at this point where the lack of general consensus appears. There are numerous alternative theories that have been offered, from Foundationalism and Coherentism to Contextualism and the Causal Theory. What these theories are proposed by experts to do, and what they are usually criticized by other experts for not adequately doing, is satisfactorily counter the two primary challenges facing any inside-out understanding of knowledge. These two challenges are the so-called "Gettier Example", and the so-called "Brain-in-a-Vat Argument".
Gettier examples are scenarios where P is true, S believes that P is true, and S has what initially appears to be properly justifying reasons for believing that P. Gettier examples are constructed as counter-examples for the various alternatives offered for understanding just what "proper justifying reasons" really means. The counter-example scenarios are so constructed that it is purely accidental that P is true despite the justification that S might have for believing that P. (S might still have what theory suggests should be adequate reasons for believing that P, even though it is not the case that P.) Gettier examples are important for highlighting our intuition that we cannot properly claim to know that P if our reasons for believing that P are not "properly related" to the truth of P. Yet the experts have experienced great difficulties in coming up with a sound understanding of just what that "proper relation" is. From the perspective of S, in these Gettier examples, it is impossible to discern whether or not one's reasons for believing that P are "properly related" to the fact that P. The truth of P is something that transcends any reasons that S might have for believing that P. As a result, some experts find themselves driven to externalist theories of justification -- interpreting the meaning of "proper justifying reasons"i n a way that is not directly accessible to S.
The Brain-in-a-Vat argument claims that because, ex hypothesi, I have no evidence ("properly justifying reasons") for believing that I am not a Brain-in-a-Vat, I cannot therefore know that I am not a BIV. And if I cannot know that I am not a BIV, then I cannot know many of the things that I normally take myself to know. It seems eminently reasonable to propose that if I know that I have two hands (a common thing to know), that would imply that I am not a BIV (since a BIV would not have two hands). Yet if I can't claim to know that I am not a BIV, then that would imply that I cannot know that I have two hands. Clearly an unreasonable conclusion. Since the conclusion is unacceptable, much effort has gone into explaining where and how the logic of such a reasonable sounding argument has gone astray. The logic of the argument is clearly sound if we accept the very reasonable sounding hypothesis that knowledge is closed under known entailment (if I know that P and I know that P imples Q, then I know that Q). Some experts, therefore, have found themselves driven to theories that deny that knowledge is closed under known entailment.
What Robert Nozick proposed in 1981(1) was to step
outside the standard tripartite model of knowledge, and examine our concept of
knowledge from the outside rather than the inside. Nozick focussed on our
intuition that the reasons that justify our claims to knowledge must be
"properly related" to the fact that P. "Knowledge is a particular way of being
connected to the world, having a specific real factual connection to the world:
tracking it."(2) He therefore proposed to examine knowledge as
something that must "track the truth". In other words, Nozick replaces Platonic
justification with subjunctive conditionality. The "subjunctive conditional" understanding results in a truth-tracking model of knowledge that maintains
S knows that P iff (1) P is true, and
(2) S believes that P; and
(3) if P were not true, S would not believe that P; and
(4) if P were true, S would believe that P.
[clause (3) is commonly known as the variation condition, and clause (4) as the adherence condition.]
More formally, taking into consideration that a consistency
of method needs to be stipulated, and that the adherence condition needs to be
understood in broad terms, the Truth-Tracking model of knowledge maintains that
S knows that P iff (1) P is true, and
(2) S believes (via some method M) that P, and
(3) If P were false, S would not believe (via M) that P, and
(4) If P were true under other circumstances,
S would still believe (via M) that P.
The key advantage with Nozick's Truth-Tracking theory of knowledge is that it satisfactorily resolves the BIV sceptical argument. The truth-tracking model entails that knowledge is not in fact closed under known entailment. Suppose I am (or am not) a BIV. Then by clause (4), I have no method (M) of coming to believe that I am (or am not) a BIV. Hence I do not know whether I am or am not a BIV. Yet, suppose I have two hands. By clause (3), if I did not have two hands, I would see by observation I did not have two hands. And by clause (4), under other circumstances, I would see by observation that I have two hands. Hence I do in fact know that I have two hands. It is therefore quite acceptable to not know whether or not one is a BIV, and yet still be able to know such common facts as that I have two hands.
The key problem with Nozick's Truth-Tracking theory of knowledge is that it can still be challenged by Gettier counter-examples. The theory as it stands does not satisfactorily address the intuition that in order to properly claim to know that P, one's reasons for believing that P must be "properly related" to the fact that P. It still remains possible that the method (M) that S employs to come to believe that P may generate a "falsely justified" belief that P. It is still possible that (i) P is true; (ii) S believes that P is true through some method M that nevertheless is not "properly related" to the fact that P; (iii) If P were in fact false, S would not believe (via M) that P; and (iv) If P were true under other circumstances, S would still believe (via M) that P because his method (M) is not "properly related" to the fact that P. Despite the method being employed by S, it remains possible that P is true accidentally. Suppose, for example, that I am a BIV, and the Vat (aka "God") advises me that I am a BIV. Then (i) it is true that I am a BIV; (ii) I believe, because "God" told me, that I am a BIV; (iii) if I were not a BIV, then "God" would not have told me I was a BIV, and I would not believe that I was a BIV; and (iv) if I was a BIV under other circumstances, "God" would still have advised me that I was a BIV. Sounds good. And yet, whether I am or am not a BIV is not "properly related" to whether "God" advises me that I am a BIV. It is quite conceivable that the particular "God" involved in this scenario could advise me that I am a BIV when in fact I am not, or that I am not a BIV when in fact I am. There appears to be a missing link in the truth-tracking theory that could provide the necessary "proper relation" between the fact that P, and S's belief that P. The only redress appears to be a demand that whatever (M) is, it is a reliable method that "properly relates" the fact that P to S's belief that P. (For example, one would have to add the assumption to the BIV scenario that "God" did not tell lies.) Yet that un-detailed demand for "reliability" leaves the truth-tracking model of knowledge in exactly the same boat as the tripartite theories of justification. And specifically, the various reliablist versions of justification.
Other criticisms of the Truth-Tracking model of knowledge focus on the fact that the model does not deal with the issues of justification and the intuition that S must have "proper justifying reasons" for believing that P. It merely mentions that S must employ some method M for coming to believe that P, without going into any details. There is no place in Nozick's model for the intuition that for S to properly claim to know that P, S must be aware (to some greater or lesser extent) of the reasons why s/he has formed the belief that P. In addition, the model does not address the intuition that knowledge claims represent a discriminative judgement on the part of S. There is no place in the truth-tracking model for the intuition that for S to properly claim to know that P, there must be some form of rational judgement on the part of S that his belief about P is knowledge rather than mere opinion. The model seems to leave the door open for "intuitive guessing", or "hunches", (and perhaps ESP?) as an appropriate way of forming a true belief.
I must also briefly mention the
"possible worlds" interpretation of Nozick's truth-tracking subjunctive
conditionals. On this interpretation, the variation and adherence conditions
would be phrased as
(3) in the closest possible worlds where P is false (unlike actuality), S no longer believes that P; and
(4) in all other close possible worlds where P is also true, S does believe P.
When thinking in terms of "possible worlds", it is assumed that we live in one possible world that we arbitrarily call "actual". It is, however, readily conceivable that things could have been different in any of an infinite number of ways. When we imagine an alternative possibility to the way things "actually" are, then that is an alternative "possible world". The greater the discrepancy from reality, the more "distant" that possible world is from actuality.
The possible worlds interpretation has the advantage of offering some people a more convenient/comfortable/graspable way of understanding the truth/success criteria of the subjunctive conditionals of Nozick's theory. The problematic subjunctive "S would (not) believe" gets translated into a selection of possible worlds where "S does (not) believe". On the other hand, the possible worlds interpretation relies on the concept of one possible world being more or less "close" to another. Since this concept is just as indefinable as the truth/success criteria of the subjunctive "S would (not) believe", nothing concrete is added to the basic theory. It just replaces one intuitive grasping with another. This is not necessarily a bad thing, of course, if one alternative is found easier to deal with than the other. It just must be realized that it adds nothing substantive to the theory.
In conclusion, it should be noted that the Truth-Tracking model of knowledge is not at all inconsistent with the Tripartite model. It is just an outside-in view of knowledge claims, rather than the traditional inside-out view. It looks at knowledge claims from a perspective not involving S's appreciation of the situation. As such, perhaps it is more appropriate to avoid examining the Truth-Tracking model as a competitor of the Tripartite models. And instead consider the truth-tracking description of knowledge as an outsider companion to the standard insider approach of the tripartite alternatives. If the companion approach is taken, then one can mate the truth-tracking model with (say) the contextualist model of justification. And one would wind up with an understanding of "knowledge" that would both resolve the BIV argument as per the truth-tracking model, and resolve the Gettier examples as per either the contextualist model of justification, or the truth-tracking model of knowledge depending on the details of the example. The truth-tracking model supports the denial that knowledge is closed under known entailment, defusing the BIV reasoning. The contextualist model of justification would ensure that S requires sufficiently supportive justifying reasons for any belief that P. And the truth-tracking model would ensure that those reasons track the truth. Thus the combination would adhere to both the common intuitions about knowledge that neither model does separately.
(1) Nozick, Robert. Philosophical Explanations. Oxford University Press, 1981.
(2) ibid. Pg 176.
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