Gábor Forgács, Tihamér Margitay, Zsolt Ziegler
Dept. of Philosophy and the History of Science
1111 Budapest, Egry J. st. 1. E 610.
[email protected], [email protected], [email protected]
www.filozofia.bme.hu
Coherentism
Truth and Justification
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What are the conditions for a belief to be true?
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Intuitively we say that observation statements are true, however we saw in
an earlier class that this is far from obvious
What is justified belief? What are the conditions of
justification?
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Justification is an inferential procedure. You give reasons for each of the
infrential steps and transfer the truth value from statement to statement.
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Presupposition: An overall and comprehensive definition of 'justification' can
be formulated.
Epistemology
Problem of regress
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Given some statement P, it appears reasonable to ask for a
justification for P. If that justification takes the form of
another statement, Q, one can again reasonably ask for a
justification for Q, and so forth.
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There are four possible outcomes to this process:
1.
the series is infinitely long, with every statement justified by some other
statement
2.
the series forms a circle (loop), so that each statement is ultimately involved
in its own justification
3.
the series ends with unjustified beliefs
4.
the series terminates with certain statements having to be self justifying
Epistemology
The Regress Argument
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P1: There are beliefs which can be justified only if there are other
justified beliefs.
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P2: The justification of the belief leads to the infinite or ends at an
unjustified belief or runs in a circle or there are self-justified beliefs.
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P3: The infinite reasoning cannot be a proper justification of our beliefs.
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P4: The circular reasoning cannot be a proper justification of our beliefs.
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P5: Appealing to unjusified belief cannot be proper justification.
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P6: There are no self-justified beliefs.
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C: None of our beliefs are justified.
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Epistemology
Foundationalism’s Answer
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Foundationalist rejects P6.
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She maintains that there must be some beliefs that, for some reason, do
not need justification. (self-justified, fundamental beliefs)
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Classical form:
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1. The basic beliefs are about my present state sensory experience. („Now it
seems to me a red circle”.)
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2. These beliefs are considered infallible, unquestionable, incorrible.
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3. Other beliefs can be derived from the basic beliefs.
Epistemology
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Epistemology
Coherence theory of epistemic justification
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Coherentist denies that there are fundamental beliefs.
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Coherentism insists that it is always reasonable to ask for a justification for
any statement.
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The justifyability of a belief is determined jointly by all of one’s beliefs taken
together.
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Coherentist argues that foundationalism provides an arbitrary spot to stop asking
for justification.
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But it does not provide reasons to think that certain beliefs do not need
justification.
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Epistemology
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Epistemology
Coherentism
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The central idea of coherentism is that the justification (justifiedness) of a
belief depends on its coherence with other beliefs.
Belief p is justified if belongs to coherent system of beliefs.
Unlike foundationalism, there are no basic beliefs and non-basic beliefs
(none of our beliefs have special, epistemic role).
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Question: How can define 'coherence'?
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Neurath’s metaphor:
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"We are like sailors who must rebuild their ship upon the open sea.”
"[…] among these are beliefs telling us ow to go about modifying this very stock of
beliefs, adding new ones and rejecting old ones.”
Epistemology
Coherentist response to the regress argument
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Coherentist denies P4 (circular reasoning).
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Of course coherentist accept that there are some circular arguments which are
fallacious.
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(Obvious examples of circularity)
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But not all circular reasonings are fallacious.
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The „great” circles are not necessary fallacious.
Coherentist denies P3. (infinite reasoning)
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The regress argument makes the assumption that the justification for a proposition
takes the form of another proposition: P" justifies P', which in turn justifies P.
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Denies that justification has a linear, „tree-like” structure.
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For coherentism, justification is not a linear, but a holistic process.
Epistemology
Taxonomy of coherence theories
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Coherence theories differ in the role of reasons and in terms of the terms of the
nature of those reasons
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Linear coherence theories are more closer to fundationalism, however they deny the
existence of epistemically fundamental beliefs. The justification of a belief rests on an
individual belief or a set of beliefs rather than on the system as a whole

Holistic coherence theories investigate the relationship between a certain belief and
all other beliefs. Justifiedness stands in the relationship with other beliefs.

Positive coherence theories require the justification of each individual belief. S is
required to have positive reasons for the acceptance of those beliefs
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Negative coherence theories do not require justification, they require the refutal of a
certain belief
Epistemology
Example
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
You received a package from a friend, who you think lives in Szeged. However
the address states that the package arrived from Debrecen. This does not
cohere with your hypothesis that ‘X lives in Szeged’ and ‘this package was sent
by X’.

After opening the package you realize a piece of ham inside. It is not the sort of
gift you would expect from a friend…

Moments later you recall your last discussion when your friend mentioned that
he has a special method of making ham, and you should taste it sometimes.
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Epistemology
Justification by coherence
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You now have a coherent pattern of beliefs and might be justified in believing
that it was your friend who sent the package.
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If you come to believe this on the basis of the pattern, you (have a justified
belief).
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A kind of incoherence with our beliefs prevents you from justifiedely believing
your first hypothesis
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You have several options in order to make your belief system coherent.
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But later, as relevant pieces of the pattern developed, you became justified in
believing this, and (presumably) came to know, that your friend sent the
package.
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Epistemology
Coherentist's account of justification
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The justification of a belief is not a (entirely) linear process.
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The end of justification process: we make certain that belief p is (logically)
connected with our system of previous beliefs.
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If our system of beliefs (B) is justified and p is coherent with B, then p is
justified.
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And a belief (q) which is item of set B, is justified, if q is coherent with another
beliefs of set of B., etc.
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Holistic justification:
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A justified belief is more like answering a question in the light of a whole set of
relevant information than like deducing a theorem by successive inferential steps
from a set of axioms (basic beliefs).
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Epistemology
Coherence and Consistency
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Let’s think of a coherent set of belief as logically consistent.
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Contradiction (example): 'A and not-A'.
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A set of belief contents, p1, …. pn, is coherent only if p1, …. pn
neither includes, nor logically entails, a contradiction.
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However, the preface paradox and the lottery paradox still maintain their
relevance.
Epistemology
Objections to Coherence as Consistency
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What about fairy tales?
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Statements in a fairy tale can constitute a logical consistent set. But of
course it would irrational to believe in a fairy tale.
There can be several coherent (consistent) systems of beliefs which are
inconsistent with each other.
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But B and B' systems (which are inconsistent with each other) cannot be equally
true.
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Possible response: The coherent system of beliefs must be comprehensive and large
enough.
But a paranoid can have a consistent and comprehensive set of beliefs (but of
course his beliefs are not justified or rational.)
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Conclusion: logical consistency is not sufficient for coherence (and
justification).
Epistemology
Argument against coherentism
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Logical consistency is not sufficient for justification
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We have a lot of justified beliefs. If justification requires coherence, each
of us has coherent system of beliefs. But is it a psychologically realistic
picture?
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And we have a plenty of beliefs, how can we check that there is no
logical inconsistencies among them?
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The logical connections between our beliefs are not entirely transparent
to us.
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The demonstration of consistency would be an extremely complex and
long process (if it is possible).
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Epistemology
Incoherent and Justified Beliefs
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The Lottery Paradox
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Imagine a fair lottery with a thousand tickets in it.
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Each ticket is so unlikely to win that we are justified in believing that it will
lose. So we can infer that no ticket will win. Yet we know that one of the
tickets will win .
„The Preface Paradox”
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Imagine an historian who has just completed her lifelong book project.
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She has double and triple checked each claim that she makes in the book,
and each has checked out.
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For each of the claims she makes, c1, ….. cn, she has a justified belief that it
is true:
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She has the justified belief that c1 is true, the justified belief that c2 is true, …
, and the justified belief that cn is true.
Epistemology
Incoherent and Justified Beliefs
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At the same time, the historian is fully aware of the fact that
historians make mistakes. Likely, her book contains at least one
mistake.
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For this reason, she believes that at least one of the claims that
she makes in her book is false. (it can be considered a justified
belief, because we have reasons to think that every book contains
at least one mistake.)
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She believes that c1 is true, the belief that c2 is true, … , the
belief that cn is true, and she has a belief that at least one of c1
through cn is false.
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But this yields a set of beliefs that is not logically consistent
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Therefore her set of beliefs are not justified. (it is paradox)
Epistemology
Isolation Objection or Input Problem
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
It concerns the relationship between a system of beliefs and the
external world.
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Coherentism seems to be a theory that allows coherence to imply
justification even when the system of beliefs is completely cut off
from individuals’ direct experience of the world around them.
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A system of empirical beliefs might be adequately justified in spite
of being utterly our of contact with the world that it tries to describe.
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Epistemology
Additional Requirements
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Explanatory relations:
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The beliefs are being explained by means of each other.
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Coherent set of beliefs needs explanatory richness.
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The toxic is steaming in the room is explained by the fact that the cap is
off the bottle of toxic liquid.
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Toxic is steaming in the room explains the fact that I am feeling sick.
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And: I am feeling sick → There must be toxic in the air → The cap must be
off the bottle. „The toxic is steaming” serves to both an explanation why I am
sick and serves as the explanatory basis for the cap being off the bottle.
An 'explanandum' is something that needs to be explained and its
'explanans' is the explanation of that phenomenon.
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Epistemology
Theories about Truth
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Theory about justification: What is justified belief?
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Theory about truth? What is truth?
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There is another theory of coherentism: the coherentist theory of truth.
They are not the same! (but it is possible to hold them together).
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Is it true that extraterrestrial life exists?
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The philosophical problem is: What does it mean to say that it is true that
extraterrestrial life exists?
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Astrobiologists study the former problem; philosophers, the latter.
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Epistemology
Correspondence Theory of Truth
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„It is true that there is extraterrestrial life.”
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Traditional answer: A proposition p is true if p corresponds to a fact (which is
expressed by the proposition).
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Truth is a certain relationship between a proposition and its corresponding fact.
(whole proposition and the fact)
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But what about universal claims? (All ravens are black. - is its a fact?)
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But what about negative claims? „There are no unicorns.” Is this a fact of the
world?
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Epistemology
Coherence Theory of Truth
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The truth of a proposition is based on the relationship between the proposition
and other propositions.
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The correspondence theory of truth differs from the coherence theory of truth in
two main respects:
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The relation between propositions
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The truth conditions of propositions
(a proposition is something that bears a truth value)
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Example: A drunk driver says: “There are pink elephants dancing on the
highway in front of us.”
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Is it true? We examine what other beliefs we have already accepted as true,
and if this believe is coherent with them, we accept this claim as true, otherwise
it is false.
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Epistemology
Coherence Theory of Truth
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We accept these propositions:
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Elephants are gray.
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This location is not the habitat of elephants.
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There is neither a zoo nor a circus anywhere nearby.
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Intoxicated persons usually have hallucinations.
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Everyone else in the area claims not to see any pink elephants.
Build on these accepted propositions, we reject that: “There are pink
elephants dancing on the highway in front of us.”
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Epistemology
Coherence Theory of Truth
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The coherence theory of truth claims that a proposition is true if and only if it
coheres with a certain set of propostions.
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Which propositons?
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1. My own beliefs. (one's own beliefs)
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2. The beliefs of the majority of persons in one’s society.
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3. The beliefs of the intellectuals in one’s society.
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4. It is consistent with all other true propositions, entails (or logically implies) all
other true propositions.
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Epistemology
Objections
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Similar objections can be formulated:
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1. There are different set of consistent propositions, which inconsistent
with each other, therefore they cannot be both true.
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2. Truth is not relative. p is coherence with my beliefs, but it doesn't
coherent with your beleifs.
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3. The conspirancy theory is a consistent, but it doesn't mean that it is
true.
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4. Our beliefs are usually considered as representing the mindindependent world. But there can be consistent sets of propositions
which don't have any connections with the reality.
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Epistemology
Conclusion
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Both the Foundationalism and Coherence theory of knowledge
have to face The Regress problem.
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Coherence theories seek justification and truth in the relationship
with other beliefs.
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Still there are several objections
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Incoherent and justified beliefs
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Input problem
Epistemology