Showing papers by "Isaac Levi published in 1976"

A Paradox for the Birds

Abstract: Does 'a is a red herring' confirm 'All ravens are black'? In some contexts, it does not. Context 1. X has already settled as part of his corpus of knowledge that all ravens are black He then makes an observation and adds to his corpus 'a is a red herring'. Clearly, the observation report does not confirm 'All ravens are black'; for the generalization is already an established part of the corpus of knowledge and is as confirmed as it could be. Of course, an observation of a black raven contributes nothing to the confirmation of 'All ravens are black' either. Context 2. X includes in his corpus of settled knowledge 'Some ravens are not black'. Once more, neither 'a is a red herring' nor 'a is a black raven' confirms 'All ravens are black'. Clearly, if 'a is a red herring' is to confirm 'All ravens are black', the truth value of the generalization cannot be settled as a matter of knowledge prior to the observation. But even in situations where the truth value of 'All ravens are black' is not decided by deduction from the corpus of knowledge, we cannot conclude that red herrings, black ravens or anything else will confirm 'All ravens are black'. Data confirm hypotheses only in contexts where these hypotheses are taken to be potential answers to some question taken as seriously meriting investigation. To illustrate, consider the following context: Context 3. X wants to find out whether some crows are black or not. On at least one plausible reading of X's question, the only consistent potential answers to his question are representable by 'Some ravens are black' and 'No ravens are black'. There is another response which can, in an extended sense, be regarded as a potential answer. X can suspend judgement between 'Some ravens are black' and 'No ravens are black'. On some occasions, suspension of judgement may be warranted by the evidence rather than the two alternatives and, in this sense, should be considered a potential answer.