It is the purpose of this paper to review the present status of discussion concerning the concept of probability. The exposition will consist of six sections: A brief statement of the most important traditional views of the concept of probability: subjective and objective; A brief criticism of two traditionally important conceptions: a priori probability and the Principle of Indifference; A criticism of an outstanding example of the subjective theory of probability, the theory of F. P. Ramsey; A criticism of the (...) most widely known of the objective logical theories of probability, the theory of J. M. Keynes; Some remarks concerning the results of the recent work of Reichenbach and von Mises with particular reference to clarification of the concept of probability; A summary of the case for the frequency interpretation of probability, revealing its basic importance in the light of present evidence. (shrink)

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Analogies must be symmetric. If a is like b, then b is like a. So if a has property R, and if R is within the scope of the analogy, then b (probably) has R. However, analogical arguments generally single out, or depend upon, only one of a or b to serve as the basis for the inference. In this respect, analogical arguments are directed by an asymmetry. I defend the importance of this neglected – even when explicitly mentioned – (...) feature in understanding analogical arguments. (shrink)

L’on considère quelques raisons en faveur du pessimisme et de l’optimisme ; et l’on arrive à ce résultat, qu’elles restent sur un terrain subjectif, où une décision scientifique entre les diverses conceptions est impossible. Pour faire de la question du pessimisme et de l’optimisme une question scientifique, il faut prendre pour problème la possibilité et la validité de l’évaluation, dans toute son étendue. Pessimisme et optimisme se transforment alors en positions, opposées l’une à l’autre, de la philosophie des valeurs, le (...) pessimisme niant totalement la validité des jugements de valeur, que l’optimisme affirme. (shrink)

The temporal pattern of the terminal response on periodic schedules depends on when responding begins. Pigeons pecking on fixed-interval and fixed-time schedules of food reinforcement responded, or accelerated, faster the later in an interval they began responding.

REASON AND ARGUMENT by P. T. Geach. Blackwell, 1977. xi + 99 pp. £4 cloth, £ 1.75 paper.