• Korean Journal of Logic
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• v.14 no.3
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• pp.27-59
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• 2011

This paper concerns several versions of conditionalization. In particular, I will examine the relationship between Jeffrey conditionalization and the second order conditionalization concerning updating higher order credences. In section 2, I suggest explicitly what Jeffrey conditionalization and the second order conditionalization are. I will argue in section 3 that Jeffrey conditionalization conflicts with van Fraassen's Reflection Principle while the second order conditionalization doesn't. And I will also argue in section 4 that under some situations, Jeffrey conditionalization may lead agents to Moorean absurdity while the second conditionalization may not. As a result, I will claim that Jeffrey conditionalization is better than the second order contionalization at updating our higher order credences.

• Korean Journal of Logic
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• v.18 no.2
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• pp.167-195
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• 2015

This paper aims to respond to Weisberg's claim that the standard Bayesian epistemology cannot model an agent's belief updating that is triggered by some undermining evidence. Our epistemological intuition seems to require that the undermining evidence decreases some particular relevant credences. According to Weisberg, however, such a belief change cannot result from the standard Bayesian belief updating rules-i.e., (Jeffrey) Conditionalization. This is because probabilistic independence between some propositions is preserved under (Jeffrey) Conditionalization on the relevant evidence. Yet I will show in this paper that this conclusion is somewhat hasty. In particular, I will show that there is another version of Conditionalization and that when one updates her credences by means of such a version, the belief updating originated in undermining evidence can be well modeled in the Bayesian framework. Some authors often call the version Higher Order Conditionalization.

• Korean Journal of Logic
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• v.16 no.2
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• pp.155-187
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• 2013

The main objective of this paper is to vindicate the Bayesian belief updating rule, i.e. conditionalization. For this purpose, I introduce first what I call Irrelevance Principle, and show that this principle is equivalent to conditionalization. In turn, the principle is vindicated by means of Bayesian confirmation theory. That is, I suggest some theses that Bayesian confirmation theorists should accept, and prove that if Irrelevance Principle is violated, the theses cannot holds.

• Korean Journal of Logic
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• v.21 no.3
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• pp.321-352
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• 2018

This paper is intended to examine a relationship between the Principal Principle and Conditionalization. For this purpose, I will first formulate several versions of the Principal Principle and Conditionalization in Section 2. In regard to the relationship between the two norms in question, I will show in Section 3 that the Principal Principle and Conditionalization are complementary in two particular senses. The first complementarity is that we don't have to formulate every version of the Principal Principle if the credences evolves by means of Conditionalization. The second complementarity is that we don't have to require for rational agents to update overall credal state by means of Conditionalization if the agent satisfies the Principal Principle. This result can be regarded as a result that criticizes and supplements some existing works about the relationship between the norms.

• Korean Journal of Logic
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• v.14 no.2
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• pp.105-121
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• 2011

The late professor Young-Jung Kim advanced a view that Existential Specification Rule (ES Rule) can be understood as a kind of polylemma. In arguing for this view, he also claimed that all propositions containing free variables are universal propositions. In this paper, I argue that his view on free variables incur numerous problems. Moreover, I introduce a new rule of inference called 'Universalized Conditionalization Rule' (UC Rule), so that I can show that his insight about ES Rule can be substantialized without an appeal to his problematic view on free variables. Finally, I show that ES Rule can be directly derived from UC Rule.

• Korean Journal of Cognitive Science
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• v.24 no.4
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• pp.323-338
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• 2013

There are multiple process mechanism in causal reasoning, which is estimation of the causal strength between cause and result. Further, because these mechanisms operate on different time phase during causal reasoning, it is highly possible that different individual difference factors are related to individual mechanisms of causal reasoning. Especially, the phenomena of conditionalization and discounting reflect attention to multiple potential causes when people infer the relationship between cause and effect. In this study, we manipulated self-construal which is an individual difference factor that reflects context sensitivity in cognition. As results, no difference was observed in conditionalization between individuals with an independent self-construal and those with an interdependent self-construal. However, independent self-construal group was observed to be lower in discounting than the interdependent self-construal group. The results indicate that conditionalization and discounting are independent cognitive process in human causal reasoning.

• Korean Journal of Logic
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• v.11 no.2
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• pp.93-125
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• 2008

The radical probabilitists deny that propositions represent experience. However, since the impact of experience should be propagated through our belief system and be communicated with other agents, they should find some alternative protocols which can represent the impact of experience. The useful protocol which the radical probabilistists suggest is the Bayes factors. It is because Bayes factors factor out the impact of the prior probabilities and satisfy the requirement of commutativity. My main challenge to the radical probabilitists is that there is another useful protocol, q(E|$N_p$) which also factors out the impact of the prior probabilities and satisfies the requirement of commutativity. Moreover I claim that q(E|$N_p$) has a pragmatic virtue which the Bayes factors have not.

• Korean Journal of Logic
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• v.19 no.3
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• pp.369-400
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• 2016

If we learn that 'Mrs Lee has two children and at least one of them is a daughter', what is our credence that her two children are all girls? Obviously it is 1/3. By assuming some other obvious theses it seem to be argued that our credence is 1/2. Also by just supposing we learn trivial information about the future, it seem to be argued that we must change our credence 1/3 into 1/2. However all of these arguments are fallacious, cannot be sound. When using the conditionalization rule to evaluate conformation of a hypothesis by an evidence, or to estimate credence change by information intake, there are some points to keep in mind. We must examine whether relevant information was given through a random procedure or a biased procedure. If someone with full information releases to us particular partial information, an observation, a testimony, an evidence selected intentionally by him, which means the particular partial information was not given by chance, or was not given accidentally or naturally to us, then the conditionalization rule should be employed very cautiously or restrictedly.