Absence of evidence IS evidence of absence

Rei/All,I think there's two scenarios going on here that aren't being separated, & that is the context within which the absence exists. As always, an analogy serves best. That I cannot find my car keys on my kitchen table is evidence that they are absent from the kitchen table. It isn't evidence (trust me!) that they aren't in the kitchen, they're probably on the microwave. The absence only becomes meaningful when the whole picture is being looked at.In science we rarely have the luxury of being able to search the kitchen, & so claiming that the non-existence of something in scenario XYZ is evidence of total absence is flawed. The best that can be said is that isn't where I have searched so far.In fact, logic has a name for this kind of shenanigan, an argument from ignorance; it hasn't been proven to exist, therefore it doesn't.MarkPS Rei, remember that argument over PE we had? Well I'm currently reading The Structure of Evolutionary Theory by Gould, & he admits he was probably wrong to insist on the association between cladogenesis & morphological change. We should give him credit for this almost death bed recantation (it was first published a month or so before his death), I'm glad he wasn't as stubborn as his reputation indicates. It would have saved an hour or so's posting if I'd known that before, anyway!------------------
"The primary purpose of a liberal education is to make one's mind a pleasant place in which to spend one's time" - Thomas Henry Huxley

DNAunion, It is specific evidence that they are not on the kitchen table, not that they aren't in the kitchen at all. So in the case that involves the entire kitchen where only one part has been searched, absence of evidence isn't evidence of absence. It is evidence of absence as regards the kitchen table, however.I appreciate you aren't making claims of absolute proof, but are making tentative claims as regards the quality of evidence, yet you are unable to make even these claims (in this situation), as I hope to show.The keys are either in the kitchen, or they aren't, they are either 100% there, or they are 100% not there. Assume there are five locations in the kitchen where they might be, the table, the drawer, on the microwave, on the shelf, or in my pocket. In eliminating the table, the keys are STILL either 100% there, or 100% not there. The probability of their existence hasn't dropped to 80%. It is a binary off/on proposition. Therefore, the fact that that they are not on the table hasn't allowed you to make any tentative conclusions as regards the likelihood that the keys are in the drawer, on the microwave, on the shelf, or in my pocket.That the keys aren't on the table isn't evidence that they aren't in the kitchen.Mark------------------
"The primary purpose of a liberal education is to make one's mind a pleasant place in which to spend one's time" - Thomas Henry Huxley

.[This message has been edited by mark24, 11-09-2003]