Subject (philosophy)

In philosophy, a subject is a being which has subjective experiences or a relationship with another entity (or "object"). A subject is an observer and an object is a thing observed.

Subjectivism in probability

In probability, a subjectivism stands for the view that probabilities are simply degrees-of-belief by rational agents in a certain proposition, and which have no objective reality in and of themselves. For this kind of subjectivist, a phrase having to do with probability simply asserts the degree to which the subjective actor believes their assertion is true or false. As a consequence, a subjectivist has no problem with differing people giving different probabilities to an uncertain proposition, and all being correct. See Bayesianism.

Related Topics:
Probability - Bayesianism

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In attempting to justify subjective probability, Bruno de Finetti created the notion of philosophical coherance. According to his theory, a probability assertion is akin to a bet, and a bet is coherant only if it does not expose the wagerer to loss if their opponent chooses wisely. To explain his meaning, de Finetti created a thought-experiment to illustrate the need for principles of coherancy in making a probabilistic statement. In his scenario, when someone states their degree-of-belief in something, one places a small bet for or against that belief and specifies the odds, with the understanding that the other party to the bet may then decide which side of the bet to take. Thus, if Bob specifies 3-to-1 odds against the theory of evolution, his opponent Joe may then choose whether to require Bob to risk $1 in order to win $3 if the theory of evolution is revealed to be true, or to require Bob to risk $3 in order to win $1 if evolution proves false. In this case, it is possible for Joe to win over Bob. According to de Finetti, then, this case is incoherant.

Related Topics:
Bruno de Finetti - Philosophical coherance - Thought-experiment

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