Limits of Justification and Basic Statements.
Do we know that we have Hands?
Glenda Satne1
1. The Problem
In the last years, Pryor, Wright and Davies, among many others, have discussed
Moore´s argument about the existence of the external world.
The argument is the following:
Evidence (e): I see a hand
this justifies
Premise1: There is a hand here
Premise 2: If there is a hand, then the external world exists
(since a hand is a material object that exists in space)
Conclusion: The external world exists.
There is something clearly awkward about this argument. Does it mean that my
perceptive experience of having a hand justifies the existence of the external world?
2. Contemporary Answers (Wright-Davies2 and Pryor)
Both Wright and Davies give a negative answer to the aforementioned question. Even
if it is true that we have perceptive justification to claim that “There is a hand”, it is not true
that this justification could be transmitted through the entailment3.
1
University of Buenos Aires – National Council for Scientific and Technological Research - Argentina
2
I will focus here only on Wright´s position since Davies has recently accepted Pryor´s point. Vid. Davies
(2004)
3
The idea is that being justified is a property that could be transmitted through entailment but
becoming more justified is not. We may consider an example: We can know p non-inferentially, know
that if p, then q, but nevertheless not be entitled to know q non-inferentially. Non-inferentially knowing
is not transmitted through entailment. The question here is that sometimes the new information that
we possess may have decreased the probability of the conclusions that we infer, even if it allows us to
make the inferences. Thus, the evidence may provide the subject with justification to believe that p, the
What happens in the case of Moore´s argument?
The idea is that there is something in the structure of Moore´s argument that makes
that the justification for the first premise “There is a hand here” could not be transmitted to
the conclusion.
Wright offers the following examples to illustrate what is wrong in this argument.
These are inductive arguments.
SOCCER:
(e): I hear that someone cries “Goal!”
This evidence provides a justification for
Premise 1: Someone has just scored a goal.
Conclusion: A game of soccer is taking place.
This argument presents some kind of special vice. According to Wright’s analysis, the
justification that we have for the premise does not transmit to the conclusion. And that is
because the conclusion must be presupposed for evidence (e) to be evidence for premise1,
evidence favoring that someone scored a goal excluding other scenarios such as one where a
film in which a soccer game takes place is being shot, etc.
In Wright’s opinion, Moore’s argument is completely analogous:
(e) I see a hand
This evidence justifies
Premise1: There is a hand here.
Conclusion: There is an external world.
(since a hand is an object existing in the external world)
The problem is once again that for (e) to be evidence that justifies premise 1 we do
need to already be justified in believing the conclusion.
So the only way in which my belief that I do have a hand is justified is through my more
general and previously justified belief that there is an external world. Then, even if Moore´s
subject may know as well that if p, then q, but this same evidence may cause the subject to be less
justified to believe q than he was before.
argument is valid, it cannot transmit more justification to the statement that there is an
external world.
Pryor has argued against this position claiming that Moore´s argument can transmit
more justification to the belief that the external world exists through experiences with hands.
His idea is that it is necessary to distinguish two properties of arguments: (1) the
capability of transmitting or not more justification to their conclusion, the justification-tobelieve structure that the argument exhibits; (2) the rational conviction that the argument
purports for the conclusion for a rational subject to believe in it and accordingly the dialectical
effectivity that the argument has regarding an opponent that does doubt of the conclusion.
Pryor´s idea is that these arguments do not have any special problem regarding the
fact that we can effectively acquire more justification to believe that there is an external world
through our perceptual experiences with hands. The idea is that we are prima facie justified to
believe that there is a hand here and to infer from this justified belief justification to believe
the proposition that the external world exists. Nevertheless, the argument would not be
effective vis-à-vis a skeptical who doubted of the conclusion, a skeptical who had or believed
to have evidence against the conclusion of the argument. Why so? Because the belief in the
denial of the conclusion – in Moore´s case the belief that there is no external world –
undermines the justification that evidence (e) can provide to justify premise 1. If I am justified
to believe that there is no external world, then sensorial experiences with hands will not be
indications of the truth of the proposition “I have a hand here”.
A proposition is prima facie justified if a set of conditions C (set of H-hypothesis) is
satisfied where those hypothesis do not need to be independently justified4. Now, these
propositions could lose their prima facie justification when some undermining propositions of
their evidence (U-hypothesis) acquire independent justification. In the specific case of the
proposition “There is a hand here” our perceptual experience is enough to justify it. But “The
external world does not exist” is precisely one of those U-hypothesis that – if it acquired
justification – would undermine the prima facie justification that our experiences provide to
the proposition “There is a hand here”.
On the other hand, the other property that arguments have according to Pryor is the
rational conviction they produce in rational subjects. In this sense, Moore’s argument would
have a ‘vice’ because depending on the beliefs of the subject in question the argument may
not be effective to overcome doubt, particularly doubts about whether the external world
exists or not. The belief in the inexistence of the external world – justified or not – or even the
doubt – justified or not – about its existence has the power to rationally obstruct for the
subject in such states, the belief that “there is a hand here” based on her perceptual evidence.
This is precisely what happens to a subject that attributes partial or complete credibility to the
belief that the external world does not exist.
4
See the distinction between a liberal treatment of hypothesis and a conservative one in Pryor (2001)
and Pryor (2004).
3. Some advantages of Pryor´s perspective.
First, an advantage of such an approach is that it seems correct to say that if I hear that
someone shouts “Goal!” I am justified to infer from this experience that a soccer match is
taking place. This seems to be perfectly in accord to our intuitions and our behavior regarding
those experiences. Only when I come to have evidence, in the broad sense of having reasons,
for the denial of the conclusion of such arguments, I can claim that I will no longer find the
corresponding premises1 justified. Evidence (e) will no longer justify my premises.
A second advantage of this perspective is that it seems reasonable to hold a position
that does not require us for any argument we may have to have an inferential strategy that
allows us to deduce our premises from another proposition, at least potentially. Do I need to
follow an inferential strategy to justify my belief every time that I believe something in a way
justified by perception? The answer seems to be clearly no.
Nevertheless, I find a problem in Pryor´s position. It concerns the fact that in those
cases in which someone questions the conclusion of Moore´s argument, the argument will not
be dialectically effective. The reason why is that it seems that the belief in the falsehood of the
conclusion blocks the possibility for evidence (e) (for instance my perceptual experience of
seeing my hand) to justify premise 1 (I have a hand here).
Pryor´s idea seems then to be that Moore´s argument transmits justification for
someone who has not wandered in skeptical paths yet but that once that we have entered
those paths it will simply not work to persuade us rationally.
Is the skeptical right after all? There is nothing that a Moorean could do to persuade
him of his conclusion?
The answer given to this question by Pryor is that the skeptical position does not
succeed in raising a reasonable doubt, that extreme skepticism does not succeed to put
forward a reasonable case to doubt of the existence of the external world. But if he succeeded
to do it – to raise a doubt, even an irrational one -, then there would be nothing that a
Moorean could do about it to proof him wrong.
4. The third way.
In my opinion, it is possible to offer a definitive answer to this skeptical problem from a
Moorean perspective. To do that, I will present two considerations against the corollary of
Pryor´s position.
In the first place, I find very important to point out that a doubt concerning the
conclusion will only undermine the justification relation that our evidence (e) has for the
premise 1 only if the kind of evidence against the conclusion is as strong as or stronger than (e).
In my view, there are hierarchies among the kind of evidence we would be disposed to admit
as such. Perceptual evidence has a much higher amount of credibility for a rational subject
than other kind of evidence – other people testimony, among others- since they are prima
facie justified. This trait, as I will later argue for, is linked with the structure that our languagegame concerning empirical claims, doubting about them, arguing for them, etc. has. It has
nothing to do with any kind of empiricist foundationalism. Rather, it is the very structure of our
empirical practices.
Allow me in the first place to illustrate this consideration with two examples. The first
of them is an already famous example owed to Dretske5.
(e) We are in the zoo watching a zebra under normal conditions.
Premise 1: This is a zebra
Premise 2: No zebra is a mule (and in particular a mule cleverly disguised to look like a zebra)
Conclusion: This is not a mule cleverly disguised to look like a zebra6.
Let us now suppose that the reason why a subject, for instance John, doubts of the
conclusion is that a friend of his who works in the zoo has told him that zebras are disguised
mules. It is highly probable that John does not doubt for this reason of his evidence to claim
“This is a zebra” as a true statement. He would only doubt about premise1 if the evidence
against the conclusion that he has is of the same type or of a stronger one than the one he
former had, i.e. (e), for premise1.
This case reminds me of a movie, The Matrix, my second example. Neo only comes to
the conclusion that what he had in front of him when he said “this is a hand” was not a hand
when he takes the pill and thus wakes up in the vat. This means: when he has evidence as
strong as (or even of the same kind that) the one he had before regarding his perception. This
kind of evidence is the one that defeats his previous believes.
The point is that is relevant to consider which are the reasons to say that the
conclusion is rejected, in order for this to imply, at the same time, doubting the premises.
Otherwise, we would doubt about the conclusion but the relation of justification between (e)
5
6
Dretske (1970). I follow here the way Pérez Otero presents it. Vid. Pérez Otero (2006), forthcoming.
It is probable for someone to consider this argument as a case of transmission-failure because we need
previously independent justification of the conclusion in order to warrant that (e) justifies premise 1. For
example, that in normal cases disguised mules are not shown as zebras in zoos; that we are in a zoo, etc.
According to Pryor (2001, p. 6-7) this is a case where transmission failed. Nevertheless, in my opinion
what you have is a corpus of justification for premise1 which could not include the conclusion but if you
get evidence against the conclusion, then maybe the evidence (e) would not justify premise 1. This
depends on the kind of evidence you have against the conclusion and the one you formerly had for
premise1, i.e. (e). My point will be that the kind of evidence that we need to justify or undermine those
hypothesis would have to be of the right type.
and premise 1 would not be undermined or blocked. More likely, it seems that in such cases
perceptual evidence remains intact. To question the relation of justification between (e) and
premise 1 it is necessary for the justification that undermines the conclusion to be of the same
kind as the one that justifies the premises or stronger than it. This consideration is compatible
with Pryor´s position who I consider does not read off all the consequences of his own case to
the end7: Pryor claims that a premise like “there is a hand here” is prima facie justified, which
means – as we said before - that some conditions C are fulfilled and that the fulfillment of
those conditions makes p to be justified. On the other hand, such a proposition will no longer
be justified – or at least will be less justified - if an hypothesis U becomes justified, where U
describes the situation in which at least one of the hypothesis that constitute C conditions is
not fulfilled. So if C conditions to believe that p is justified include hypothesis H which claims
for example that John told me so, hypothesis U will state for instance that everything that John
says is a lie. In my opinion, these examples show that in Moore´s case the kind of U Hypothesis
capable of defeating H hypothesis (for ex. my perception that there is a hand here) should be
empirical (like perceiving that there is no hand here, that the hand is somewhere else, etc.).
The second consideration I would like to present is once again related to the possibility
of giving a definite answer to the skeptical challenge. As we said, Pryor considers that if we
had, even in an unjustified way, the belief that the external world does not exist, the rational
commitments that such a belief would lead us to assume would rationally obstruct the
possibility for us to believe that there is a hand here on the basis of our perceptual
experiences. The reason for this is that such a belief would be a U-hypothesis, an undermining
hypothesis for my justification conditions for premise1. I will maintain that such a belief, the
belief that the external world does not exist, is not even a possible belief. This second
argument I would like to present proceeds from Wittgenstein. The strategy will then be
Wittgensteinian-moorean in the sense that it follows the reading of Moore´s argument that
Wittgenstein carries on in On Certainty. Wittgenstein maintains in On Certainty that Moore
found out that there are certain statements that are prima facie justified. This means, as
Wittgenstein puts it, that there are some statements that we can not doubt of because, if we
did, the whole building of what we call knowledge would fall apart. Such statements are, so to
say, the framework of every framework that we use to doubt of what we believe. These
statements are the hinge-propositions of our language games, those propositions that belong
to the bedrock of the river along which our empirical discussions flow, discussions about
whether today is a sunny day, whether tomorrow will rain or even scientific discussions about
the atomic structure.
The argument for the existence of this kind of propositions may well be summarized as
follows: to be able to question some of our propositions some others must be presupposed. If
not, we do not even understand what means to question them (OC, 96).
Let us consider an example. Let´s suppose that John has got up early and is still not
wearing his glasses. He looks out the window and he believes to see Peter on the opposite
sidewalk. He wonders: is that Peter? To give an answer to such a question John grabs his
glasses and puts them on. He looks out the window once again and does see Peter. He thinks:
7
Vid. Note 28 in Pryor (2004).
that´s Peter. Let´s now suppose that John starts reading a book that says that he himself is not
actually other than a brain in a vat connected to a machine that makes him perceive things as
he does. He then thinks that what he saw out the window was not Peter but a figment of his
mind. What could John now do? To be clearer: What kind of glasses could help John to figure
out whether the image he sees as standing by his window is Peter or not? The answer is
obvious: there is absolutely nothing John could do.
The corollary of this example is that we cannot give any content to the purported
belief in the non-existence of the external world: empirically, this belief has absolutely no
content. This means that it cannot be a belief after all.
The proposition that there is an external world becomes thus a basic statement: basic
statements are for Wittgenstein those statements than cannot be questioned. In my reading,
this question should be read as follows: all our statements about our perceptions and based on
them imply that the external world exists8. Such a proposition cannot be doubted because it is
entailed by every empirical proposition. This means that every justified empirical proposition
justifies the proposition that the external world exists.
This Wittgensteinian issue leads us in the first place to accept that there are some
limits on justification: if it is possible to justify some of our statements, then there should be
some statements presupposed for justification to be possible9.
8
My reading here differs from the reading that Wright and others make of Wittgenstein. For them, the
proposition that the external world exists is “presupposed” as a premise in every justification that we
may have for our beliefs about what we perceive, even for those based on our perceptual experiences.
So, every argument that pretends to give more justification to the belief that the external world exists
from our experiences with hands will be vicious: it will no transmit more justification. In my opinion, the
structure of such justifications is the one Pryor purports: so all of them give more justification to the
proposition that the external world exists. This idea, together with the idea that there is a certaintydifferentiated hierarchy, imply that the only scenario where the doubt in the conclusion undermines the
justification that my beliefs give to my perceptual experiences is an empirical one. I will not argue here
that this is Wittgenstein’s position but just use some of the concepts he and others have developed to
sketch a plausible image of our exchanging-and-justifying-empirical-statements game.
9
Wittgenstein deals with the problem of the limits of justification not only in On Certainty but in the
Philosophical Investigations as well. He says (§ 217):
“’How am I able to obey a rule?’ – if this is not a question about causes, then it is about justification for my following
the rule in the way I do.
If I have exhausted the justifications I have reached bedrock, and my spade is turned. Then I am inclined to say: ‘This
is simply what I do.’
(Remember that we sometimes demand definitions for the sake not of their content, but of their form. Our
requirement is an architectural one; the definition a kind of an ornamental coping that supports nothing.)”
To offer a justification about why and how we follow some complex rules, there must be some
basic cases about which we could only say: that I show we behave. It is possible that if someone asks me
under what conditions I am entitled to castle the King in a chess game I could answer offering an
argument like the following: “If neither the King nor the castle have been moved, and there are no
The distinction between knowledge and certainty developed by Wittgenstein becomes
then a distinction between propositions than can be doubted and those that cannot, at least in
some sense.
Among the latter belong with the highest degree of evidence10, those we are less
disposed to doubt of, those that are prima facie justified such as “There is a hand here” or yet
better “This is my hand”. These are for Wittgenstein hinge-propositions, precisely because of
the role the play in our language-games with empirical propositions; they are always taken as
true and are the basis of every empirical assertion. Only in very special circumstances it makes
sense to doubt of them. Wittgenstein offers the following example. An accident has taken
place. I wake up, maybe still on shock, and see some meters away from me a hand. I may then
well ask: “Is that my hand?”
Among certainties we find as well according to Wittgenstein the proposition that the
external world exists. In the reading I am presenting, a Wittgensteinian reading in a broad
sense, this means that it is entailed by every empirical proposition. Besides, Wittgenstein
accepts that any proposition is itself empirical. According to me, this means that there are
some empirical (and only empirical) scenarios that would put it into doubt and that would then
undermine the prima facie justification that our experiences provide to our empirical
statements.
5. Dialectical effectivity.
We could now ask to what extent this consideration, if they were correct, imply that
Moore’s argument has to be considered dialectical effective vis-à-vis the skeptic. It is relevant
for this purpose the distinction between the first and the second person.
I will start considering the first person perspective. From the point of view of the first
person, the only justification that someone can offer for “There is a hand here” is “This is how I
behave” or “This is how I see it”. This would be the corollary that Wittgenstein extracts from
Moore, and the point that we have been making through the concept of prima facie
justification. However, there may be some specific circumstances under which these
statements could be questioned – like in the case of the accident -. The limits on justification
that these statements establish are relative to the context in which they are used. In some
contexts they represent the limit for justification, in others, more unusual, they may be
questioned. Such questioning can be modalized using Pryor’s theoretical framework.
pieces between them, I may castle the King” and since I have not moved the King nor the castle and
there are no pieces between them I may castle the King. But if my opponent kept asking about how I
know that I have not moved the King or, finally, how I know that this is my hand or that having the time
for me stopped someone moved the King and then moved it back, and so on, I would simply not have
anything to answer to him. This kind of statements does not belong to our usual language games.
10
Prima facie justified propositions that we referred to before.
It seems as well correct to me to accept that all our experiences back up or justify our
belief in the existence of an external world, as Pryor does. That is to say that I accept that
justification is transmitted from the premises to the conclusion (against Wright). When I wake
up in the morning after having dreamt that a bomb exploded causing the known world to
vanish, or that I was a brain in a vat, I see my hand, and I say to myself that everything is all
right; that there is an external world and that is my perception what entitles me to believe
that.
Let us then consider the second person perspective. This is precisely the context where
an opponent doubts about the conclusion of Moore´s argument, asking me to offer an extra
justification for this statement. The answer is that such a statement is presupposed in our
empirical game of justifying – it is presupposed in the sense specified above: it is entailed and
justified by our empirical propositions -. It is the kind of thing that cannot be questioned in the
context of the game of giving reasons about which of our statements are true and asking for
them. Regarding the second person perspective, then, it is not simply the case, as Pryor claims,
that the arguments are not dialectally effective; the skeptical defy can not even be made. We
cannot give any sense to the proposition that the external world does not exist because its
contradictory is presupposed in the game of justification for empirical propositions in general,
since it is entailed by all our empirical basic statements. The assertion that the external world
does not exist turns out to be a mere rhetorical strategy to which we cannot assign any precise
content11.
Departing from these considerations a problem could raise: according to the first
critical observation, we must take into account the kind of evidence that rejects the conclusion
and as a consequence the background against which the statement about the existence of the
external world could be questioned depends on the kind of evidence that we have. Thus, if the
conclusion that there is no external world received empirical justification, then the link
between perceptive evidence and “there is a hand here” would be broken, while if the
evidence that we have against the existence of the external world is merely conceptual or by
testimony, such a link will not be broken. But: How is that compatible with Wittgenstein´s
claim - which I have supported - that this is a basic statement and cannot be doubted?
The answer is that it is always possible that new evidence shows us that there is no
external world. This is the case because the statement “The external world exists” has
empirical content. It has to be then accepted that new evidence can refute this statement, but
11
In this sense, such a hypothetical belief would play the role that Pryor assigns to pathological doubts.
These do not affect the property of a belief of being well-founded i.e. beliefs that I am not only justified
to believe, that are based on that justification and that besides are rational, to which there are no other
beliefs that rationally oppose to them or that rationally obstruct them. Vid. Note 38 in Pryor (2004),
where he claims that if a subject pathologically believed that he is a brain in a vat, his perceptual beliefs
would be equally well-founded. I maintain that beliefs such as “the external world does not exist” would
be pathological, in the sense that they would not affect our well-founded beliefs as in the sense that
their content is not even clear.
also that in that scenario the meaning of the word “evidence” would change and our justifying
practices should correlatively change as well12.
6. Finally, the answer: what sounds funny in Moore’s argument?
According to Wright and Davies, the answer to the question above is clear: what fails in
Moore’s argument is its justification structure. The perceptual justification of the premises
cannot be transmitted to the conclusion because the conclusion itself is needed and
presupposed so as that our perceptual experience can justify the rest of our empirical
propositions, e.g. that I have a hand when I see it. I have argued that this reconstruction of the
argument is wrong. The proposition “there is a hand here” is a basic proposition that is not
justified through other propositions but that is prima facie justified only through our
perception. So, the structure of the argument regarding justification transmission from the
premises to the conclusion does not present any defect. Justification does transmit from the
premises to the conclusion. The only particular thing about it is that if we acquired justification
against the conclusion and we got to doubt about it, then the relation between our perceptual
evidence and propositions based on it would be undermine. We can then admit an epistemic
dependence from the premises to the conclusion but it is not a vicious one13.
Pryor has presented this alternative way of understanding the justification structure of
Moore’s argument and I agree with it. Nevertheless, regarding the question about why
Moore’s argument is awkward, Pryor maintains that the argument is not dialectical effective.
The point is that besides having a justification structure, arguments can either persuade or not
those subjects that take them into consideration of the truth of their conclusions. In Pryor’s
view, if a subject has beliefs – even unjustified beliefs – that rationally oppose to the premises
or conclusions at stake or that rationally obstruct believing them on the basis of certain
grounds14, then such a subject is committed to doubt of the propositions or not to believe in
them. Thus, vis-à-vis a skeptic who doubted of the conclusion of Moore’s argument, such an
argument would not be dialectically effective, i.e. would not persuade him rationally, and
12
OC, 108. This is the corollary of Wittgenstein´s observation that we would not understand someone
who told us that had been to the moon or would go to it. The text was finished in 1951. We could say
that the kind of statements that we accept now, after 1969, are different, given that new experience has
defeated them: no philosophical dream about possible worlds where we travelled to the moon was
previously enough to give sense to such a statement.
13
Pryor calls this epistemic dependence ‘type 4-dependence’ and distinguishes it from type-5
dependence, the one typically vicious; those arguments where justification for the conclusion is needed
to justify the premises. This is the structure of Moore’s argument according to Wright and the one the
zebra-argument has according to Pryor. It is the justification structure that the petitio principii exhibit,
where the justification that I have for the premises actually does not transmit to the conclusion.
14
Such is the case when a justified or unjustified belief undermines the justification relation between
those grounds and the premise or the conclusion at stake.
would not be enough for him to overcome the doubt. And that is so because doubting the
conclusion rationally obstructs for that subject the possibility of justifying empirical
propositions based on his own perceptual experiences.
In my opinion, this line of thought of Pryor is not appropriate: the capability that
arguments have to persuade rationally does not depend on the audience that takes them into
consideration; on the contrary, it lies on the intrinsic qualities of the arguments regarding
precisely their structure. Otherwise, we would have broken the natural link that exists
between correct argumentation and persuasion, to such an extent that we will be in big
trouble to put them together again. A completely different issue is how to account for
irrational beliefs or irrational discursive persuasion.
Going back to the original question, that is, why Moore’s argument sounds funny, and
even philosophically inadequate as an answer to skepticism, we could give a twofold answer.
On one hand, since the proposition that states the existence of the external world is entailed
by every empirical proposition, it is not strange that it sounds at least redundant that an
argument in its favor has been given, an argument precisely based on one of these trivial cases
that naturally lead us to such a conclusion. On the other hand, this argument brings into light
the empirical condition of this hinge-proposition of our empirical practice and by those means
exhibits the scenario where we could refute it. Well understood, such a possibility, far away
from justifying skepticism, shows that the refutation could only be itself empirical15.
15
It is worth noting that empirical evidence of such a kind that could undermine the justification that
the proposition “The external world exists” has could be acquired as evidence against the fulfillment of
C-conditions. Thus, the corresponding premise 1 would be no longer justified and would not then
transmit justification to the conclusion. Other kind of undermining experiences would require
justification. For example, the Matrix case requires empirically showing that it is possible to see a hand
where there is not actually any hand.