The Truthmaking Solution to the Gettier Problem

In 2003 I set out a new solution to the Gettier problem that had bedevilled the theory of knowledge. Here I want to describe that solution and make some personal remarks as to its genesis and subsequent history. (All the relevant papers can be found on

The idea is easily described. Let us take the second of Gettier’s own counterexamples to the idea that knowledge is justified true belief (and no more than that) — that is, the idea that in having a justified true belief one has satisfied the sufficient conditions for knowledge. Jones has good reasons to believe that Brown drives a Ford, in the form of Brown’s own testimony and his (Jones’s) own observations. Jones picks a set of cities that begin with the letter ‘B’: Barcelona, Brest-Litovsk, Boston, say, and then forms propositions for each such city, of the kind:

Either Brown owns a Ford or he is in Barcelona,

Either Brown owns a Ford or he is in Brest-Litovsk…

Jones believes each of these propositions simply because he believes on good evidence that Brown owns a Ford, and this is the first disjunct of each of these sentences. (It must be emphasised that the disjunction here must be understood as inclusive disjunction.) It turns out however that Brown does not own a Ford but that he is in Brest-Litovsk. Thus this sentence is true and believed on good grounds, and hence is justified — despite the fact that Jones has no reason at all to believe that Brown is in Brest-Litovsk. It must be emphasised that this problem rests on us sharing Gettier’s intuition that under this circumstance Jones does not know that Either Brown owns a Ford or he is in Brest-Litovsk but that his belief is both true and justified. Most people have shared this intuition — but if one doesn’t then one will not see a problem here. At any rate I do share Gettier’s intuition.

The truthmaker solution to this and similar Gettier problems is that the truthmaker for the sentence — the state of affairs that makes it true — is not, as it normally would be, the state of affairs of which Jones has evidence. Instead we have two different states of affairs, one of which is the truthmaker, and the other of which the evidence for the belief is evidence of. Thus all of these classical Gettier cases involve a doubling of the states of affairs that are involved. Thus I proposed an analysis of knowledge that goes as follows:

The Knowledge-conditions. X knows A iff  X believes A; X is justified in believing A; A is true; and the evidence that X has which constitutes the justification is evidence of the very state of affairs that makes A true.

In addition to what I would call the classic Gettier problems — an example of which is above — there is another set called the Ginet-Goldman cases, also called the fake barn cases. An example is as follows. Along a particular stretch of road there are many fake barn facades so skilfully done as to be indistinguishable, to the casual motorist, from the real thing. Driving along the road you form a sequence of beliefs that this is a barn, that is a barn, this next one is a barn and so on. However, one of these barn facades, call it R, is the facade of a real barn. Passing R you form the belief that is a barn. This is a true belief. Moreover you have good evidence that it is true. So it would seem that you know it is a barn. Some distinguished philosophers however have wanted to claim that it is not knowledge — simply because you also formed similar beliefs when driving past all of the fake barn facades — and in those cases your belief was false. One might say that your belief about R was true, but so embedded in a series of false beliefs that you cannot take credit for it. So it is not knowledge.

This also depends on our sharing the intuition — that the motorist here has a justified true belief but does not have knowledge. But how plausible is that intuition in this case? Certainly it must be agreed that the motorist has many beliefs that are false and that therefore do not count as knowledge. But in the case where the motorists belief is true, where the evidence is of a genuine barn nothing has gone wrong. Thus my intuition in these cases is that the motorist does have knowledge after all. And note that in this case there is no doubling of the states of affairs that are responsible for the attribution of knowledge to the motorist. So my truthmaker account deals with this view automatically.

I put this solution forward in 2003 at a conference on epistemology — in fact at the last session of the conference, when many had gone home. However the attendance at the paper was still respectable, and the conference had attracted most of the people in Australia who were centrally concerned with the theory of knowledge: Tim Oakley, John Bigelow, Anne Newstead, Michaelis Michael, etc. Along with these there were many overseas visitors. The paper was finalised by the time of the conference because I had been testing out this solution and refining it for two years, 2000 and 2001, in my epistemology classes — lectures which were then written up as the first four chapters of my book A Primer on Knowledge. It’s also worth noting that I’d been working on truthmaker theory itself, on and off, since 1995 when Kevin Mulligan was visiting the Sydney department — one result of which came out in Logique et Analyse in 2003. (It was this visit by Mulligan that propelled David Armstrong’s interest in truthmaker theory.) The point of saying this is to note that this solution did not just come out of nowhere — there was a prepared ground.

The paper, ‘Truthmaking and the Gettier Problem’ came out in 2006 in a volume of papers from the conference: Aspects of Knowing: Epistemology Essays, published by Elsevier, edited by Stephen Hetherington, who had also been the conference organiser.

In the original paper I took the view that Russell’s stopped clock example — which, historically was the first classic Gettier counterexample in the literature, published in 1948 in Human Knowledge: Its Scope and Limits — was dealt with by my account: it involves a doubling of the relevant states of affairs: the evidence is of a clock which stopped 12 (or some multiple of 12) hours earlier, whereas the truthmaker is the time that actually obtains. However an email from Gonzalo Rodriguez-Pereyra raised a doubt about this. In reply I repeated my belief that it required no more than had already been given. Over time however it seemed to me that the case was interesting enough, and complex enough, that it required further comment — and after all, what matters in philosophy is whether one has said enough to convince everyone, and not simply whether one has convinced oneself: I felt that I had done Rodriguez-Pereyra a disservice by not attempting to make the case in more detail. And so I wrote a short paper for Analysis in which I tried to lay this problem to rest — once and for all (so I hoped). (This was ‘Gettier and the Stopped Clock’, Analysis, 72, 2, 2012. See here)

The solution was this: Firstly the actual time depends on governmental stipulations and decisions, so the truthmaker in this case is partially constituted by such decisions. This does not make such facts any the less objective. Once the stipulations are in place it is an objective fact that the time is now 11.10 am. Clocks represent the correct time to us by being synchronised causally with an authoritative original clock, and with being constructed so as to “keep time”. But when you look at a clock (in keeping with Russell I am assuming that clocks are the usual 12 hour analog clocks) you do not know the time just from that looking, you use a wealth of contextual information — the position of the sun in the sky, the sound of traffic, the sounds of birds and people — to check whether the  clock is accurate or no longer running. Merely glancing at clock in the absence of this contextual information is not sufficient for forming a justified belief. Neverthelesss when the clock is running and has been properly set the evidence you acquire from looking at the clock plus this contextual information is evidence of the correct time. When the clock is stopped or slow (or fast) the evidence you acquire is of a different state of affairs — even if it happened to stop 12, or a multiple of 12, hours earlier. There is a doubling of the relevant states of affairs — so my account deals with it by adding the extra condition, as above. All is good.

Thus let us suppose that a clock stopped at 2.00 am but then suddenly started working properly at 2.00 pm of the next day — and let us suppose that no one looked at the clock in the 12 hours during which it was stopped. Then, I say, it is still not giving one a knowledge of the correct time — instead it is indicating a time that is 12 hours earlier. No one may be aware of this: but still it is so, ex hypothesi.

It should be noted that Russell himself did not claim that in looking at the stopped clock you acquired a justified true belief (that yet wasn’t knowledge). His example was meant to show merely that this was an example of a true belief that wasn’t knowledge. So my view about the stopped clock case is consistent with Russell’s own view, whereas those who believe that merely looking at a clock is enough to give you a justified belief as to the time go considerably beyond what Russell was prepared to assert. The onus is on them to make their case.

As a personal aside I might note that my grandmother worked for Russell at the end of the 1940’s and through the 1950’s — and thus through the time when he was writing Human Knowledge: Its Scope and Limits. (In fact she claimed to have saved Russell’s then wife, Patricia Spence, from committing suicide by jumping off the balcony: they were going through a particularly unpleasant divorce at the time. My aunt was Conrad Russell’s best friend in childhood — indeed one has to say his only friend.)

It should be noted that Russell not only gave the stopped clock example he also gave an example that is logically equivalent to Gettier’s first counterexample (the one not given above). He is given scant credit for his contributions to the theory of knowledge, particularly those found in his later works. The recent treatment of Russell amounts to a scandalous neglect, in my opinion.

I’ve been asked a few times how David Armstrong reacted to my solution to the Gettier problem. After all, it could be said to vindicate his idea — expressed in many later books — that truthmakers were the key to understanding Truth and many metaphysical problems. The answer is that he didn’t know of it — as far as I know. During 2003 and the time around it Armstrong was teaching in America and even when he returned I didn’t bump into him until much later. By that time the Gettier paper was old news for me and I was thinking about other things. So I don’t ever remember mentioning it to him. Which is a pity: I think he would have been chuffed.

Since the Analysis paper I’ve written a number of other papers on the topic, which are here here and here — which were all attempts at stopping the view from being misunderstood. But the misunderstandings, though unpleasant and unnecessary, were the least unpleasant aspect of a rather unpleasant subsequent development. A number of unscrupulous philosophers — four to my certain knowledge, but there may be more that I haven’t been alerted to — have attempted to take my work, reword it slightly, and claim it as their own. They have wanted to claim that they have solved the Gettier problem — though years later, in fact.  Plagiarism is NOT too strong a word for this. I think this speaks volumes about the current state of academic philosophy — but such plagiarism requires a blog post of its own.

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