In recent years philosophers have produced arguments designed to prove that not all human behavior can be predicted or otherwise known in advance, and these arguments have been taken to be relevant to the problem of freedom of the will as well as to the question whether there can be genuine behavioral sciences. Specifically, it is argued that in certain circumstances it is logically impossible that one should come to know decisions, and actions for whose occurrence decisions are necessary conditions, in advance of the occurrence of such decisions. This has been interpreted as a refutation of determinism.

Two antipredictive arguments will be presented separately, and later their import when taken together will be discussed. The first concerns the scientific defectiveness of predictions that influence the predicted event, and the second concerns the logical impossibility of a person's knowing now what he will decide only at some future...