A straw man argument is an informal fallacy based on misrepresentation of an opponent's position.[1] To "attack a straw man" is to create the illusion of having refuted a proposition by substituting a superficially similar proposition (the "straw man"), and refuting it, without ever having actually refuted the original position.[1] [2]
Presenting and refuting a weakened form of an opponent's argument can be a part of a valid argument. For example, one can argue that the opposing position implies that at least one of two other statements - both being presumably easier to refute than the original position - must be true. If one refutes both of these weaker propositions, the refutation is valid and does not fit the above definition of a "straw man" argument.
http://en.wikipedia.org/wiki/Straw_man
Presenting and refuting a weakened form of an opponent's argument can be a part of a valid argument. For example, one can argue that the opposing position implies that at least one of two other statements - both being presumably easier to refute than the original position - must be true. If one refutes both of these weaker propositions, the refutation is valid and does not fit the above definition of a "straw man" argument.
http://en.wikipedia.org/wiki/Straw_man
