A straw man argument is an informal fallacy based on misrepresentation of an opponent’s position. 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
When confronted by skeptics, as I’ve noted elsewhere, we should always carefully inspect their questions logically, in order to best determine how we should respond. In many cases, what I’ve noticed is that their arguments are guilty of a number of fallacies. For example, one fallacy that is prevalent in the field of higher criticism is the fallacy of division (as I’ve written about here). At times fallacies are enjoined to one another. If the fallacy of division is committed in respect to what the authors of the New Testament believed, then it follows that the rejection of their theology is not the rejection of the theological content actually presented in the New Testament, but a distorted form of that theology. In the final analysis, what is rejected is not the theology of the New Testament, but a “straw man” set up in its place.
The above example from higher criticism is a little more subtle; however, there are many more direct examples of this that can be found in some of the most popular skeptical literature available today (e.g. anything by Richard Dawkins). The fallacy is observed in statements like: “We don’t need God to explain why things happen the way they do, we have science.” It can also be found in an interaction between Napolean Bonaparte and French mathematician Simon-Pierre Laplace that gives us a great concrete example of the fallacy in action. From wikipedia:
Laplace went in state to Napoleon to accept a copy of his work, and the following account of the interview is well authenticated, and so characteristic of all the parties concerned that I quote it in full. Someone had told Napoleon that the book contained no mention of the name of God; Napoleon, who was fond of putting embarrassing questions, received it with the remark, ‘M. Laplace, they tell me you have written this large book on the system of the universe, and have never even mentioned its Creator.’ Laplace, who, though the most supple of politicians, was as stiff as a martyr on every point of his philosophy, drew himself up and answered bluntly, ‘Je n’avais pas besoin de cette hypothèse-là.’ (“I had no need of that hypothesis.”) Napoleon, greatly amused, told this reply to Lagrange, who exclaimed, ‘Ah! c’est une belle hypothèse; ça explique beaucoup de choses.’ (“Ah, it is a fine hypothesis; it explains many things.”)