Alan Forrester
2013-01-01 21:00:27 UTC
There has been some lack of clarity about issues concerning measuring ideas and criticism and justification. In particular there have been disputes over whether there can be any measure of the merit of an idea and if so whether such a measure is justificationist. My position is that any given idea should either be rejected or accepted in a yes/no way.
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There are several criticisms of justificationism.
The first is that any argument that supposedly justifies an idea has unexplained premises and so a justificationist has to give up on explanation.
The second is that either you keep making justificationist arguments forever or you give up and use unjustified premises in which case your idea is unjustified and you get nothing from all this justification.
Third, you can conclude that something must be wrong with your ideas if you find a contradiction among them even if none of them are justified, so you can choose between ideas by criticism. The contradiction itself doesn't have to be justified. Even if you find an apparent criticism that turns out to be wrong, you have to adopt new ideas to fix it even if they have a lot in common with the old ideas.
Fourth, justificationism is incompatible with judging ideas in terms of whether they stand up to criticism. If you want criticism you want to stretch your ideas as much as possible, try to apply them to as many problems as possible and you hope to find flaws so you can fix them. A justificationist has to try to confine an idea to issues on which he has found no flaws because if he does otherwise he is using the idea where it is unjustified and he might find a flaw in it. For examples of this phenomenon consider the philosophical cowardice of Wittgenstein and Kuhn.
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Let's consider one situation in which it might appear that an idea can have a measure that's relevant to judging its merit. Suppose I want to build a laser and that I want to build it using a diode. A given diode laser will often be destroyed if it exceeds some particular temperature. To cool the diode you can do things like attach a big block of metal to it, or a radiator, or you have pipes with water in them go past the diode and water carries away heat from the diode. The more power you put into a given diode the more heat it will have to dissipate and given a particular cooling mechanism there will be a maximum amount of power you can get out without frying the diode. So you could say something like "Given a choice between two different diodes that cost less than £x, fit in a given volume…[other stuff]...I would prefer the one that gives me more power."
There are two things to notice. First, this figure of merit is dependent on an explanation. Since explanations are all totally unjustified and unjustifiable, so too is this figure of merit. Second to make decisions between different diodes you do it on the basis of a yes/no question: "Would diode x give me more power than diode y given blah blah, blah?" So any given decision is just a binary decision: it's not "this idea has x goodness points".
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About the hard to vary idea. If hardness to vary comes in some kind of figure of merit like laser power, then I would apply the same argument as above. David proposed in FoR that knowledge bearing objects are more uniform across the multiverse than non-knowledge bearing objects: but this is just another figure of merit. This figure of merit may exist for all knowledge but using it to choose between two ideas would depend on having an explanation that it is relevant to judging between those two ideas using that figure.
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As explained in the chapter on choices in BoI, weighing is not a rational way of making decisions. One reason for this is that different explanations can't be mixed to produce a sensible result since the mixed idea will not solve problems. Another is that Arrow's theorem, which explains that there is no consistent weighing process that satisfies particular principles of rationality. You might say that those principles could just as well fit a justificationist or a critical rationalist, so there is a criticism of weighing that isn't dependent on whether we side with critical rationalists or justificationists.
So let's look at the assumptions of Arrow's theorem (agents here just means things participating in the decision, an agent need not be a person):
(1) The weighing should depend only on the preferences of the agents making the decision.
(2) The rule should not pick a single agent who always get to make the decision.
(3) If the agents are unanimous in favour of some option then the weighing selects that option.
(4) If the weighing selects A over B and some agents who preferred C switch to A, then A should still be selected.
(5) If the weighing selects A over B and C over D, and the agents change their minds about C and D but not A and B, then A should still be picked over B.
Some of these seem difficult to square with justificationism. For example, if a single agent happens to have the magical formula for justification, then why shouldn't he just get to wave his magic want and make all the decisions? I would come up with more, but one criticism is enough.
So to conclude any given idea should either be rejected or accepted in a yes/no way. Measures are relevant to this choice only insofar as there is an explanation linking that particular measure to a criterion by which we can make a yes/no decision.
Alan
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There are several criticisms of justificationism.
The first is that any argument that supposedly justifies an idea has unexplained premises and so a justificationist has to give up on explanation.
The second is that either you keep making justificationist arguments forever or you give up and use unjustified premises in which case your idea is unjustified and you get nothing from all this justification.
Third, you can conclude that something must be wrong with your ideas if you find a contradiction among them even if none of them are justified, so you can choose between ideas by criticism. The contradiction itself doesn't have to be justified. Even if you find an apparent criticism that turns out to be wrong, you have to adopt new ideas to fix it even if they have a lot in common with the old ideas.
Fourth, justificationism is incompatible with judging ideas in terms of whether they stand up to criticism. If you want criticism you want to stretch your ideas as much as possible, try to apply them to as many problems as possible and you hope to find flaws so you can fix them. A justificationist has to try to confine an idea to issues on which he has found no flaws because if he does otherwise he is using the idea where it is unjustified and he might find a flaw in it. For examples of this phenomenon consider the philosophical cowardice of Wittgenstein and Kuhn.
-------------
Let's consider one situation in which it might appear that an idea can have a measure that's relevant to judging its merit. Suppose I want to build a laser and that I want to build it using a diode. A given diode laser will often be destroyed if it exceeds some particular temperature. To cool the diode you can do things like attach a big block of metal to it, or a radiator, or you have pipes with water in them go past the diode and water carries away heat from the diode. The more power you put into a given diode the more heat it will have to dissipate and given a particular cooling mechanism there will be a maximum amount of power you can get out without frying the diode. So you could say something like "Given a choice between two different diodes that cost less than £x, fit in a given volume…[other stuff]...I would prefer the one that gives me more power."
There are two things to notice. First, this figure of merit is dependent on an explanation. Since explanations are all totally unjustified and unjustifiable, so too is this figure of merit. Second to make decisions between different diodes you do it on the basis of a yes/no question: "Would diode x give me more power than diode y given blah blah, blah?" So any given decision is just a binary decision: it's not "this idea has x goodness points".
----------------------
About the hard to vary idea. If hardness to vary comes in some kind of figure of merit like laser power, then I would apply the same argument as above. David proposed in FoR that knowledge bearing objects are more uniform across the multiverse than non-knowledge bearing objects: but this is just another figure of merit. This figure of merit may exist for all knowledge but using it to choose between two ideas would depend on having an explanation that it is relevant to judging between those two ideas using that figure.
----------------------
As explained in the chapter on choices in BoI, weighing is not a rational way of making decisions. One reason for this is that different explanations can't be mixed to produce a sensible result since the mixed idea will not solve problems. Another is that Arrow's theorem, which explains that there is no consistent weighing process that satisfies particular principles of rationality. You might say that those principles could just as well fit a justificationist or a critical rationalist, so there is a criticism of weighing that isn't dependent on whether we side with critical rationalists or justificationists.
So let's look at the assumptions of Arrow's theorem (agents here just means things participating in the decision, an agent need not be a person):
(1) The weighing should depend only on the preferences of the agents making the decision.
(2) The rule should not pick a single agent who always get to make the decision.
(3) If the agents are unanimous in favour of some option then the weighing selects that option.
(4) If the weighing selects A over B and some agents who preferred C switch to A, then A should still be selected.
(5) If the weighing selects A over B and C over D, and the agents change their minds about C and D but not A and B, then A should still be picked over B.
Some of these seem difficult to square with justificationism. For example, if a single agent happens to have the magical formula for justification, then why shouldn't he just get to wave his magic want and make all the decisions? I would come up with more, but one criticism is enough.
So to conclude any given idea should either be rejected or accepted in a yes/no way. Measures are relevant to this choice only insofar as there is an explanation linking that particular measure to a criterion by which we can make a yes/no decision.
Alan
------------------------------------
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