An "ancestral" is a kind of relation that is a sort of generalization of a more specific relation. It's easiest to explain this by means of an example. Consider the relation "being the parent of" This is a relation that holds between any person who has a child and that child, for example, Henry Fonda and Jane Fonda. Of course Henry Fonda was himself the child of another person -- maybe George Fonda. And George was the child of yet another person, Sarah Fonda, and so on. So we could, by going back through the generations, build a list of individuals, where each individual is the parent of the next individual on the list. So consider the "Fonda List." Every person on that list is related to Jane in some way. Henry is her parent, George is her grandparent, Sarah is her great-grandparent, etc. But is there some way to talk about an arbitrary person on this list? There is! We can say that every person who is on this list is an *ancestor* of Jane's. Someone -- say Patrick -- is an ancestor of Jane...

Ordinary usage of these terms is inconsistent, and so, to some extent, is the technical usage. Sherlock Holmes is said to have solved crimes through "deduction." A philosopher would say, no, his methods were non-deductive. "Inductive" is often, in philosophy, opposed to "deductive", yet the kind of proof that in mathematics is called an "inductive" proof, is, by standard philosophical definitions, deductive. So no wonder you're confused. Nobody owns these terms, so no one can rightfully say that anyone else's usage is objectively correct or incorrect. But let me give you at least one way of understanding the terms, and then an explanation in terms of that understanding for all the weirdnesses. I tell my students in Intro Philosophy that the difference between "deductive" and "non-deductive" arguments has to do with the way the premises of the argument are supposed to support the conclusion of the argument. In a deductive argument, the author of the argument is claiming that the premises...

Whew! What you have here is a real smorgasbord of fallacies. Let's sort them out. One fallacy here -- and I think this is the one you primarily have in mind -- is a fallacy called "attack ad hominem ", which means "attacking the person." This is the fallacy of attacking the character or credentials of the person making the argument, instead of showing what's wrong with the argument itself. In the example you give, Chomsky claims that US foreign policy was partly responsible for the 9/11 attacks, and offers considerations d, e, and f. To attack Chomsky's argument , one would have to either give grounds for thinking that d, or e, or f was false -- that is, show that the argument contained a false or unsupported premise -- or else show that d, e, and f did not logically entail the conclusion (if the argument is meant to be deductive) or did not provide good evidential support for the conclusion -- that is, show that the argument was not valid (bad if the argument was supposed to be...

I have a few things to say in response to your question. First of all, about whether too high a value is placed onrationality in “Western” culture: I feel that rationality is too little valuedin the United States at the moment, and that irrationality is celebrated. An extremely popular trope in US books,movies, and television shows is the heroism of a person who “believes” – that is, who accepts on faith something thatflies in the face of all evidence and logic. The skeptic, the “man (usually) of science,” is always shown to bewrong, often disastrously so. And manypeople report with great pride that they hold their particular religious orpolitical beliefs on the basis of no evidence or reason at all. “It’s just what I believe.” Secondly, as to the nature of our cognitive processes. You’re raising a perfectly sensible empiricalquestion – what are the neurological processes that account for the phenomenawe call “thought”? It’s clear...