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2. Reason / A. Nature of Reason / 6. Coherence

[principles of mutual support between propositions]

24 ideas
A rational account is essentially a weaving together of things with names [Plato]
     Full Idea: Just as primary elements are woven together, so their names may be woven together to produce a spoken account, because an account is essentially a weaving together of names.
     From: Plato (Theaetetus [c.368 BCE], 202b)
     A reaction: If justification requires 'logos', and logos is a 'weaving together of names', then Plato might be taken as endorsing the coherence account of justification. Or do the two 'weavings' correspond?
Maybe everything could be demonstrated, if demonstration can be reciprocal or circular [Aristotle]
     Full Idea: Some optimists think understanding arises only through demonstration, but say there could be demonstration of everything, for it is possible to demonstrate in a circle or reciprocally.
     From: Aristotle (Posterior Analytics [c.327 BCE], 72b16)
     A reaction: I'm an optimist in this sense, though what is being described would probably best be called 'large-scale coherence'. Two reciprocal arguments look bad, but a hundred look good.
If one proposition is deduced from another, they are more certain together than alone [Russell]
     Full Idea: Two obvious propositions of which one can be deduced from the other both become more certain than either in isolation; thus in a complicated deductive system, many parts of which are obvious, the total probability may become all but absolute certainty.
     From: Bertrand Russell (Regressive Method for Premises in Mathematics [1907], p.279)
     A reaction: Thagard picked this remark out, in support of his work on coherence.
Full coherence might involve consistency and mutual entailment of all propositions [Blanshard, by Dancy,J]
     Full Idea: Blanshard says that in a fully coherent system there would not only be consistency, but every proposition would be entailed by the others, and no proposition would stand outside the system.
     From: report of Brand Blanshard (The Nature of Thought [1939], 2:265) by Jonathan Dancy - Intro to Contemporary Epistemology 8.1
     A reaction: Hm. If a proposition is entailed by the others, then it is a necessary truth (given the others) which sounds deterministic. You could predict all the truths you had never encountered. See 1578:178 for quote.
Coherence is consilience, simplicity, analogy, and fitting into a web of belief [Smart]
     Full Idea: I shall make use of the admittedly imprecise notions of consilience, simplicity, analogy and fitting into a web of belief, or in short of 'coherence'.
     From: J.J.C. Smart (Explanation - Opening Address [1990], p.06)
     A reaction: Coherence sounds like a family of tests, rather than a single unified concept. I still like coherence, though.
We need comprehensiveness, as well as self-coherence [Smart]
     Full Idea: Not mere self-coherence, but comprehensiveness belongs to the notion of coherence.
     From: J.J.C. Smart (Explanation - Opening Address [1990], p.07)
Reasoning aims at increasing explanatory coherence [Harman]
     Full Idea: In reasoning you try among other things to increase the explanatory coherence of your view.
     From: Gilbert Harman ((Nonsolipsistic) Conceptual Role Semantics [1987], 12.2.2)
     A reaction: Harman is a champion of inference to the best explanation (abduction), and I agree with him. I think this idea extends to give us a view of justification as coherence, and that extends from inner individual coherence to socially extended coherence.
Reason conservatively: stick to your beliefs, and prefer reasoning that preserves most of them [Harman]
     Full Idea: Conservatism is important; you should continue to believe as you do in the absence of any special reason to doubt your view, and in reasoning you should try to minimize change in your initial opinions in attaining other goals of reasoning.
     From: Gilbert Harman ((Nonsolipsistic) Conceptual Role Semantics [1987], 12.2.6)
     A reaction: One of those principles like Ockham's Razor, which feels right but hard to justify. It seems the wrong principle for someone who can reason well, but has been brainwashed into a large collection of daft beliefs. Japanese soldiers still fighting WWII.
A coherent conceptual scheme contains best explanations of most of your beliefs [Harman]
     Full Idea: A set of unrelated beliefs seems less coherent than a tightly organized conceptual scheme that contains explanatory principles that make sense of most of your beliefs; this is why inference to the best explanation is an attractive pattern of inference.
     From: Gilbert Harman (Rationality [1995], 1.5.2)
     A reaction: I find this a very appealing proposal. The central aim of rational thought seems to me to be best explanation, and I increasingly think that most of my beliefs rest on their apparent coherence, rather than their foundations.
A false proposition isn't truer because it is part of a coherent system [Cartwright,R]
     Full Idea: You do not improve the truth value of a false proposition by calling attention to a coherent system of propositions of which it is one.
     From: Richard Cartwright (Intro to 'Philosophical Essays' [1987], xi)
     A reaction: We need to disentangle the truth-value from the justification here. If it is false, then we can safely assume that is false, but we are struggling to decide whether it is false, and we want all the evidence we can get. Falsehood tends towards incoherence.
If the only aim was consistent beliefs then new evidence and experiments would be irrelevant [Goldman]
     Full Idea: If mere consistency is our aim in achieving a coherent set of beliefs, then new evidence and experiments are irrelevant.
     From: Alvin I. Goldman (The Internalist Conception of Justification [1980], §VIII)
     A reaction: An important reminder. What epistemic duty requires us to attend to anomalous observations, instead of sweeping them under the carpet?
We may end up with a huge theory of carefully constructed falsehoods [Fraassen]
     Full Idea: The specter that faces us is that we may end up having explained all that is dreamt of in our philosophies by intricately crafted postulates that are false.
     From: Bas C. van Fraassen (The Empirical Stance [2002], 1.5)
     A reaction: This is more persuasive that Idea 12769. People who cannot bear to live with a total absence of explanation (with Keats's 'negative capability') are most in danger from this threat.
We can't attain a coherent system by lopping off any beliefs that won't fit [Sosa]
     Full Idea: Coherence involves the logical, explanatory and probabilistic relations among one's beliefs, but it could not do to attain a tightly iterrelated system by lopping off whatever beliefs refuse to fit.
     From: Ernest Sosa (Beyond internal Foundations to external Virtues [2003], 6.4)
     A reaction: This is clearly right, so the coherentist has to distinguish between lopping off a belief because it is inconvenient (fundamentalists rejecting textual contradictions), and lopping it off because it is wrong (chemists rejecting phlogiston).
Why should we prefer coherent beliefs? [Klein,P]
     Full Idea: A key question for a coherentist is, why should he or she adopt a coherent set of beliefs rather than an incoherent set?
     From: Peter Klein (Infinitism solution to regress problem [2005], 'Step 1')
     A reaction: The point of the question is that the coherentist may have to revert to other criteria in answering it. One could equally ask, why should I believe in tables just because I vividly experience them? Or, why believe 2+2=4, just because it is obvious?
The negation of all my beliefs about my current headache would be fully coherent [Sosa]
     Full Idea: If I have a headache, I could have a set of beliefs that I do not have a headache, that I am not in pain, that no one is in pain, and so on. The resulting system of beliefs would cohere as fully as does my actual system of beliefs.
     From: Ernest Sosa (The Raft and the Pyramid [1980], §9)
     A reaction: I think this is a misunderstanding of coherentism. Beliefs are not to be formulated through a process of coherence, but are evaluated that way. A belief that I have headache just arrives; I then see that its denial is incoherent, so I accept it.
Coherence can't be validated by appeal to coherence [Bonjour]
     Full Idea: The epistemic authority of coherence cannot itself be established by appeal to coherence.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §3.7 n50)
     A reaction: The standard approach amongs modern philosophers (following, I think, Kripke) is to insist on 'intuition' as basic, despite all its problems. I have no better suggestion.
For any given area, there seem to be a huge number of possible coherent systems of beliefs [Bonjour]
     Full Idea: The 2nd standard objection to coherence is 'alternative coherent systems' - that there will be indefinitely many possible systems of belief in relation to any given subject area, each as internally coherent as the others.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 3.2)
     A reaction: This seems to imply that you could just invent an explanation, as long as it was coherent, but presumably good coherence is highly sensitive to the actual evidence. Bonjour observes that many of these systems would not survive over time.
Coherence is a primitive, intuitive notion, not reduced to something formal [Shapiro]
     Full Idea: I take 'coherence' to be a primitive, intuitive notion, not reduced to something formal, and so I do not venture a rigorous definition of it.
     From: Stewart Shapiro (Philosophy of Mathematics [1997], 4.8)
     A reaction: I agree strongly with this. Best to talk of 'the space of reasons', or some such. Rationality extends far beyond what can be formally defined. Coherence is the last court of appeal in rational thought.
Coherence problems have positive and negative restraints; solutions maximise constraint satisfaction [Thagard]
     Full Idea: A coherence problem is a set of elements connected by positive and negative restraints, and a solution consists of partitioning the elements into two sets (accepted and rejected) in a way that maximises satisfaction of the constraints.
     From: Paul Thagard (Coherence: The Price is Right [2012], p.42)
     A reaction: I'm enthusiastic about this, as it begins to clarify the central activity of epistemology, which is the quest for best explanations.
Coherence is explanatory, deductive, conceptual, analogical, perceptual, and deliberative [Thagard]
     Full Idea: I propose that there are six main kinds of coherence: explanatory, deductive, conceptual, analogical, perceptual, and deliberative. ...Epistemic coherence is a combination of the first five kinds, and ethics adds the sixth.
     From: Paul Thagard (Coherence: The Price is Right [2012], p.43)
     A reaction: Wonderful. Someone is getting to grips with the concept of coherence, instead of just whingeing about how vague it is.
Explanatory coherence needs symmetry,explanation,analogy,data priority, contradiction,competition,acceptance [Thagard]
     Full Idea: Informally, a theory of explanatory coherence has the principles of symmetry, explanation, analogy, data priority, contradiction, competition and acceptance.
     From: Paul Thagard (Coherence: The Price is Right [2012], p.44)
     A reaction: [Thagard give a concise summary of his theory here] Again Thagard makes a wonderful contribution in an area where most thinkers are pessimistic about making any progress. His principles are very plausible.
Coherentists seek relations among beliefs that are simple, conservative and explanatory [Foley]
     Full Idea: Coherentists try to provide an explication of epistemic rationality in terms of a set of deductive and probabilistic relations among beliefs and properties such as simplicity, conservativeness, and explanatory power.
     From: Richard Foley (Justified Belief as Responsible Belief [2005], p.317)
     A reaction: I have always like the coherentist view of justification, and now I see that this has led me to the question of explanation, which in turn has led me to essentialism. It's all coming together. Watch this space. 'Explanatory' is the key to everything!
How can multiple statements, none of which is tenable, conjoin to yield a tenable conclusion? [Elgin]
     Full Idea: How can multiple statements, none of which is tenable, conjoin to yield a tenable conclusion? How can their relation to other less than tenable enhance their tenability?
     From: Catherine Z. Elgin (Non-foundationalist epistemology [2005], p.157)
     A reaction: Her example is witnesses to a crime. Bayes Theorem appears to deal with individual items. "The thief had green hair" becomes more likely with multiple testimony. This is a very persuasive first step towards justification as coherence.
Statements that are consistent, cotenable and supportive are roughly true [Elgin]
     Full Idea: The best explanation of coherence (where the components of a coherent account must be mutually consistent, cotenable and supportive) is that the account is at least roughly true.
     From: Catherine Z. Elgin (Non-foundationalist epistemology [2005], p.158)
     A reaction: Note that she is NOT employing a coherence account of truth (which I take to be utterly wrong). It is notoriously difficult to define coherence. If the components must be 'tenable', they have epistemic status apart from their role in coherence.