Meeting the Master Objection
theories are regularly confronted with the objection that there can be many
coherent systems, so that mere coherence is said to be insufficient as either
the defining element of truth or even as a working criterion of truth. This
objection has been called the “master objection”. If someone is taking
coherence not only as a criterion supporting the truth of a theory, but as an
ingredient to a definition of “true” she has to attack the master
objection straight on.
you start with the set of all statements of a language. Now you construct
maximal consistent subsets of this set, given some (standard) logic. You
arrive at what? – The set of all possible worlds (descriptions of possible
worlds) with respect to the language and logic in question. These sets differ
as to what regularities or universal generalizations they support. The
question which of these sets (i.e. which of these possible worlds) is the most
coherent cannot have an answer – unless there is an a
priori way to single out the actual world, assuming it to have the most
coherent description! That would be strange indeed, since arriving at the
best theory of the world would not involve any empirical knowledge whatsoever.
So even if there are aspects of coherence besides consistency that serve to
exclude some candidate sets as candidates for the best theory, a multitude
of candidate coherent sets remains.
first attempt to reduce the multitude of coherent systems is to require
coherence with a privileged set of statements. This has led, for example,
Laurence BonJour in coherence theory to include an observation requirement:
The privileged set of statements are the observational truths. Suppose there
is a set of data or observational truths. Fictions, however coherent, seem to
be immediately in trouble to cohere with the data. No one ever met Sherlock
what are the data?
can start with the data accepted at that very moment. Since this set (of
observation statements) certainly is not complete – we are not omniscient
– and contains statements to which no facts correspond – we are not immune
from error – it has to be allowed to drop some of the members of this set.
Which supposed data are to be discarded and which data are to be added
is already part of the coherent theory building starting from this data set.
building involves that data support theoretical beliefs by causing
the act of perceiving something there might be something else than a
proposition. The content of a perception is not a proposition. A state of
affairs (something that can be expressed by a proposition) might be referred
to, but it is given by an analogical representation. The percept (the scene
before our eyes) is a qualia complex (a gestalt). It is propositionally
embedded only in frames like
I see that: ô
contrast to propositions in the frame
I believe that p.
content of (1) after the “that” is no proposition. Therefore it cannot
enter directly into relations with other propositions. But the states of
perception are the causes of believing propositions. Some truth conditions or
ostensive introductions to the proper use of some term directly relate terms
to percepts, for example
(3) “is a smiley” is true of x in English iff x looks like that: :-) [a smiley]
perceptual input stands in conventional and/or causal relations to
observational beliefs or observational statements considered to be true.
External facts having to do with the reliability of the believer need not be
known to the believer at this stage of theory building.
in the most simple procedure we proceed as follows:
steps 4 revisions of the set of believed observational statements may occur.
substantial aspect of coherence might count “explanatory power”,
“simplicity (of ontology)” or “multiple connections between
coherence with the data presupposes some level of data, of observation given
independently of the theory choice under consideration (see §4), but it
need not presuppose that the data are given to us completely independent of
any considerations of coherence (see §3).
Empirical Equivalent Theories?
we consider the question how criteria of theory choice work with respect to
“empirically equivalent theories”, we have to make clear what empirical
equivalence is. If empirical equivalence is taken to be the result of having
employed all our methodological tools (i.e. our aspects of coherence), then we
have answered the question about the role of the aspects of coherence in
theory choice already in the negative. The claim of the existence of empirical
equivalent theories is taken thus only a version of the master objection. To
avoid this we have to emphasize the “empirical” in “empirical
equivalence” and make sure that empirical equivalence occurs at some stage
of theory formulation or at some stage at which further theory choice (by some
aspect of coherence) is applicable.
empirical equivalence is more than having two theories share a body of data.
Empirical equivalence also concerns the predictions that can be derived in
these theories respectively. If observational information is defined as the
information present in observation statements (of the level concerned, cf. §4),
empirically equivalent theories are those which have the same amount of
observational information. Two theories can have the same amount
of observational information although the one leaves out some data the other
one explains, and vice versa. In
this sense empirically equivalent theories do not have to agree on all data!
On the narrow notion of empirical equivalence (i.e. sharing all predictions)
two theories can have a problem simultaneously, because one prediction (made
by both of them) turned out to be false. On the wider notion of empirical
equivalence we would say that two theories are still empirically equivalent if
the severity of their problems with different predictions turning out wrong is
question is whether there can be empirically equivalent theories in one of
these senses, both of which satisfy some aspect of coherence, but which
logically exclude each other.
Duhem-Quine-Thesis states that no
single statement implies evidential consequences all by itself, but only
within the body of a theory. This is also the coherentist`s view. And since
the consequences of a statement have to be established relative to a theory
something is wrong with foundationalism. Nevertheless it is wrong to
conclude from this that we (always) have a choice whom to blame in case of a
failure of a prediction. The route from the theoretical background to
evidential consequences is implication, but in the case of disconfirmation
coherence principles like explanatory power might be so strong as to select
only one culprit, without an equally good option to rebuild some other part of
the theory. Coherence is a theory about the kind of inferential relations
within a theory (i.e. these being not hierarchical). It is not
primarily a theory about alternatives in revision!
that any explanation in theory T can be matched by others in theory T* which
fit the data equally well. How are we to decide which is true? Success in
predicting data does – by assumption – not help us. We may employ some
standards of systematicity. Suppose now, second assumption, that once again we
come to several equally good explanatory systems. We may try now a standard of
simplicity. This is justified since by assumption both theories considered
are equally reliable, any meta-justification referring to the reliability of a
practise based on the theories is going to fail in discriminating between
them. We could stick to those explanations which are close to our typical
explanation up to now, but can this prejudice be justified? So it seems that
we face the alternative of just sticking to our idiosyncratic standards –
leading straight to relativism – or to point to some a priori
standard of sufficient reason (whether this will be a rich notion of
explanatory power alone or a set of coherence principles).
is a functional/trancendental argument for the prima
facie truth of observational beliefs : If our observational beliefs
were not true most of the time communication, successful action, introduction
of language would be impossible. Since these are obviously possible and cannot
be reasonably put into question we may assume that our observational beliefs
are true most of the time. That is having an observational belief is a reason
to taking is prima facie to be true. We might explain observational
beliefs as the result of complex cognitive processes, but assuming them to be
true does not require knowing this cognitive theory.
mistake of foundationalism is to posit beliefs which are completely
justificatory independent of other beliefs. That is obviously false, as the
information that you are under the influence of drugs puts the truth of your
observational reports into doubt. In pure foundationalism the data are
neutral with respect to any theory. This makes it almost impossible to give up
a supposed datum. One has to assume some (physiological) malfunction (in the
brain) of the observer. Adherents of a moderate foundationalism (like Robert
Audi) take up some ideas of coherentism and use the concept of negative
evidential dependence, which means that an observational belief can be
undercut by additional knowledge as to non-normal circumstances. The
observational belief, which otherwise is prima facie taken to be true,
is retracted. This feedback on the observational belief can happen only at its
entering into the body of belief.
are two stages at which considerations of coherence enter. First there is the
stage at which the observational belief is about to enter into body of belief.
Observational beliefs entering causally into a body of beliefs is important
for any theory of knowledge inclined towards naturalism. Beliefs – at least
in a computational theory of the mind – depend causally on other beliefs.
Assume there is a network defined by causal relations/dependencies. In such a
network justificatory relations can be causal relations although there is no
hierarchy of justification. Dependence might exist inasmuch as some input into
the network causes changes which give rise to beliefs which, therefore, depend
on the input. “Data” might be just another word for “input” in such a
beliefs can be taken to be immediate. They arise because of our causal
embeddedness in the environment. We prima
facie believe them because of our background theory of observation. But
this does not make observational beliefs temporally dependent on the
theoretical beliefs. The picture is rather that the theory is a possible
interrupter in the etiology of beliefs. Usually the observational belief is
not interrupted and causes further change in the web of belief. What changes
of belief it causes depends on how the observational belief enters into applications
of regularities. This is the second stage at which considerations of
coherence enter. Now the observational belief is part of the data which can be
considered the preferred set which theories have to be in coherence with. But
depending on the changes in our theories that could be arrived at given that
we take the observation to be true we might give up this very observational
belief – for the sake of better coherence. This way of giving up an
observational belief should not be confused with the mechanism of undercutting
mentioned in the first stage.
In the first stage we built the set of observation statements that our other statements have to cohere with. The guideline of including some observation statement is a rule like
I believe the observation statement p, because
it seems to me that p, and
it does not seem to me that I do not perceive that p.
principle like (O) gives us a prima facie perceptual foundation of
beliefs. Since (b) is not as strong as “it is not the case that I do not
perceive that p” we are not back in foundationalism.
a coherentist (like BonJour) makes the doxastic presumption (of
assuming access to our beliefs) it seems that he has to admit some further
kind of foundationalism: Beliefs about which beliefs we have are the basis of
an assessment of coherence. But although beliefs about beliefs stand in need
of justification we do not have to have a justification available to have
these beliefs. The enterprise of justifying our beliefs can start without the
meta-beliefs being justified. Beliefs about beliefs will be justified in the
course of explaining our belief structure. This explanation, according to the
coherentist, sustains the doxastic presumption. It will also explain why
creatures like us are more or the less right about their beliefs.
a structuralist account of theories the language of theory T can be the
observation language for phenomena to explained by another theory T’ (of
some more theoretical level). An even stronger relative notion of observation
language can be saved once we consider the two stage process in which
coherence considerations apply to observational belief. An observational term
might be infected by the theory we eventually adopt as the best account of the
data. But this account of the data occurs only at the second stage (i.e. the
stage at which the observational statement enters into the body of our
statements believed to be true). Rival theories start out with the same set of
data, so at this stage at least, the concepts employed in the data cannot
depend on the conceptual resources of these theories (at this level). There
might be connections between our vocabulary of observation and the vocabulary
of undercutting assumptions (the theory of “normal conditions”), but
these connections occur at an earlier level of building up our best
representation of reality (an earlier level of theory building in a wider
will be a lowest level of theory building, one might presume. So one
might suppose a lowest observation language. At this level the observational
terms are at most invested with theoretical assumptions of former theories
which were taken up into the definitions – if there are any – of the
observational expressions. Some of the observational expressions may be free
of any theoretical assumptions worth mentioning and may, therefore, be the
proper target of conditional learning. At this level we may speak of
“stimulus meaning” in the proper sense. We accept some observation
statement since we are conditioned to this acceptance response given our
causal input. Subjectively an observation statement is true, because it fits
our perception of the situation. In intersubjective reasoning we give reasons
why we hold observation statements to be true, why the situation is really of
the kind described. Doing this we consider whether they fit in at some level
of theory building, as it should be.
are compared with respect to the aspects of coherence synchronically. We
accept the empirically adequate theory which is more coherent, whatever else
may be its relation to its rivals. It need not entail them. It need not entail
their consequences. Since coherence as considered here contains a data
requirement, any theory passing the coherence test will ipso
facto save the phenomena.
respect to the continuity of science it is desirable that a successor theory
explain the merits and failures of its predecessors (e.g. by paying
attention to limiting conditions), or
build upon the referential framework of a predecessor (e.g. by claiming
to refer to the same entities not withstanding the prior mode of their
this is possible a theory within such a historical thread is superior to a
completely new theory since it inherits a success history.
claim that we access our beliefs and that we have access to the principles of
coherence. The latter cannot mean that we are fully aware of the consistency
or explanatory status of our whole body of beliefs. This is implausible and
maybe impossible for us to do because of computational complexity if we
consider beliefs which arise because of this meta-knowledge. It is probably
psychologically not feasible to access simultaneously a very great number of
beliefs from long term memory. We could refuse, however, to accept that knowledge
depends on having checked the inconsistency of our whole body of beliefs. The
issue of computational complexity might be an argument itself that we proceed conservatively:
As long as we have no further evidence consistency and other epistemic
valuable properties of our body of beliefs are assumed on the basis of only
modest computations. Access to the principles of coherence could just mean
that in case of argument we appeal to these or similar principles. To be able
to reason with these principles need not presuppose to keep track of our whole
body of beliefs. The principle of giving just sufficient
reasons so long as no further justified doubt arises allows to operate on
small sub-systems of belief. This could also be expressed as a principle of
conservatism. Having reached some conclusion we may reopen our investigation
later, but we need a good reason to reopen it. We stay with a theory that has
worked so far.
is no aspect of coherence itself, but a principle to shift burdens of proof.
Coherentism can account for that.
with the set of observational beliefs accepts that observational beliefs are
beliefs of higher epistemic value than others. This presupposes some theory
claiming that our perceptions and observational beliefs founded upon them
are more the less reliable. That some statement is to be considered as a
correct observation statement is not established by some other road to truth
besides coherence, but is taken as a prima facie assumption, starting
with our ordinary assumptions about us and the world we live in. It would go
against the spirit of a thorough coherence theory to start with some given
truths. It does not go against the spirit of a thorough coherence theory to
assume – on credit, so to say – that ordinary observation is more or the
less correct. This theory itself has to be defended within the wider coherent
picture of knowledge and human faculties. The whole enterprise proceeding thus
stabilizes itself by being the background theory of a successful (scientific)
practise. Intervening in reality and being successful supports the theory that
was used in the intervention. For a realist there is no cosmic exile beyond
principles of coherent theory building add up to a framework which is
quasi-transcendental. Since there are no ultimate foundations in the manner
of traditional transcendental philosophy there seems to be a lurking danger of
incommensurability. Criteria of theory choice – at least some of them –
have to be beyond dispute if we are to decide between theories. The criteria
or procedures in question probably result from our explanation of such
fundamental notions like “argument”, “explanation”,
“justification”. Somebody who proposes a theory within our language has
framed the theory already within the body of these very general rules and
pre-understandings. Somebody who wants to change our language or speaks
another language has to be interpreted. Inasmuch as the interpretation is
successful (i.e. we can distinguish his claims from given mere quotes with
respect to him) we import our logic and methodological principles – at least
in their most general form – unto the supposed theory. In short: Wherever
there is a dispute between theories the meta-criteria of coherence are
presupposed (as mutually accepted) already! Our success in identifying cases
of theory choice or alternatives supervenes on our ability to exploit this
common framework of shared concepts. We possess at least an operative/implicit
knowledge of this common core. Optimistically speaking: Wherever there is a
dispute about theory choice there are the tools to choose (at least in
principle). Pessimistically qualifying this: Even if we have this operative
faculty to identify or even solve cases of theory choice by (vaguely)
appealing to meta-criteria and criteria of coherence we might do a bad job at
explaining or even formalizing these concepts.
Strictly speaking you might say that only observation statements
are true, not beliefs themselves. Read the remarks then as applying to the
statements you are disposed to assent to because of your observational
Audi, Robert. The Structure of Justification. Cambridge, 1993.
Balzer, Wolfgang. “Holismus und Theoriebeladenheit der Beobachtungssprache”, Erkenntnis, 10 (1976).
John (Ed.). The Current State of the
Coherence Theory. Critical Essays on the Epistemic Theories of Keith
Lehrer and Laurence BonJour with Replies. Dordrecht/Boston/London,
Structure of Empirical Knowledge.
Cambrige MA/London, 1985.
Alvin. Epistemology and Cognition.
Gilbert. Change in View.
Nicholas. Cognitive Systematization.
Paul. “The Best Explanation. Criteria for Theory Choice”, The
Journal of Philosophy, 75 (1978), pp.76-92.
Ralph. The Coherence Theory of Truth.
Realism, Anti-Realism, Idealism. London/New York, 1989.
Crispin. “Critical Study: Ralph C. S. Walker, The
Coherence Theory of Truth”, Synthese,
103 (1995), pp.279-302.