In debate, the formal names for this dishonest debate tactic are “spreading” or “proof by verbosity.” Gish Gallops are nearly always employed as negative arguments in political or religious debates.
"Policy debaters started talking fast in the 1960s, when a team from the University of Houston figured out that speed allowed them to cram more arguments into a timed speech than their opponents would physically be able to negate." — Jay Caspian Kang Wired, “High School Debate at 350 WPM"
As noted in previous apologetics fails, a great number of religious assertions are trivial to advance, but take great effort to refute. Creationist Duane Gish (1921-2013), a biochemist who worked for the Creation Research Institute (there is a reason failed scientists work for Wingnut Welfare, as such organisations can parlay the alleged credentials into apparent “controversy” amongst scientists—see also climate change deniers and tobacco company supporters). He abused this debate tactic so often that “proof by verbosity” fallacy has now been named after him by the National Center for Science Education in the Nineties.
NCSE has even stated that public debates with religious apologists are pointless: The apologist will do things like pack the house with his or her supporters, while the scientist will not likely have any supporters unless that person has personal appeal for others to come to the debate (colleagues as an example). In one particular debate, Duane Gish was found to have scheduled talks at three different churches a few days ahead of a debate, and actually bussed in people from those churches to provide a crowd of supporters for him.
In formal debate, there is a question posed that the debaters take two sides on: the affirmative and the negative. In formal debate, the person or team arguing for the question posed must present arguments with evidence supporting the proposition posed. The negative person or team only needs to knock out one leg of the affirmative argument by providing evidence for the negative argument to win a debate. (I was on my high school debate team, but the rules are the same whether it’s high school, college, political, or religious debates.)
The usual procedure in a formal debate is 1) affirmative argument 2) negative argument 3) affirmative rebuttal 4) negative rebuttal.
In a Gish Gallop, the point is to spew a firehose spray of different points, as rapidly as possible, to make it impossible to refute all the negative points. Ofttimes those points are restatements of the same point, unsupported assertions, or flat-out lies. Just enough true points are included to give the gallop the veneer of “truthiness.”
As formal debates are timed, the Gish Gallop seeks to prevent the affirmative debater from addressing all the negative points. The galloper then claims victory in the debate because all of his or her points were not refuted.
Nearly any logical fallacy can be included in Gish Gallops, because the point is number of arguments, not validity of arguments.
Gish Gallops always include an unstated fallacy of appeal to authority, except the galloper doesn’t actually need to be an authority: He or she appears to be an authority by the seeming breadth of knowledge he or she has. The appeal to authority in a Gish Gallop is sometimes likened to a pie tin: wide but not deep. Those unfamiliar with the tactic (such as the general public watching a debate) go away with the impression the galloper is far more authoritative than he or she really is, and thus the gallop will lend undue credence to his or her position.
This was notoriously shown in the evolution versus creationism debate between Bill Nye (mechanical engineer who is a bowtie addict and known as The Science Guy) and Ken Ham (Answers in Genesis and director of the Creation Museum and the Ark Encounter).
Bill Nye v. Ken Ham on Evolution, full debate, two and a half hours. The debate included a packed house of Ken Ham supporters at the Creation Museum.)
Religious debaters always argue against science positions from a negative position (Evolution by Natural Selection is a favourite target, but just about anything can be, including the speed of light or a round Earth.)
Gish Gallops are most often used in religious debates (to support religion) or politics (to support weak policy or attack an opponent’s position).
As a political example, former Massachusetts Governor Mitt Romney famously used a Gish Gallop against President Barack Obama in their first Presidential debate. Polling afterwards showed that Gov. Romney “won” the debate, because the public watching it was snowed by the stream of truths, half-truths, unsupported assertions, and lies. In subsequent debates between the candidates, strict rules were put in place to prevent spreading, and Gov. Romney lost the subsequent debates.
Ben Shapiro (former writer for the hyper-conservative Website Breitbart) routinely uses Gish Gallops to make arguments for conservative political positions or Christian young-Earth creationism. In addition to Gish Gallops, Mr. Shapiro has developed the ability to speak incredibly fast, which allows him to throw out even more points. You can find examples of him debating on YouTube.
In a normal debate, the person or team taking the negative position will try to knock one or more arguments away from the affirmative position by providing an argument with well-supported evidence. In a debate, the affirmative must successfully defend against all negative attacks, while the negative position is only required to defeat one affirmative position.
As such, when a Gish Gallop is used by a religious apologist, a political pundit, or a politician, the galloper can claim victory if the person he or she is arguing against does not decisively defeat him or her on every point. If the opponent asks for evidence of the galloper’s assertions, the galloper will usually employ the “do your own research” argument. (The counter is Christopher Hitchens’s “that which is asserted without evidence can be dismissed without evidence.”)
Sometimes Gish Gallops are written up as text arguments, such as the infamous 77 Non-Religious Reasons to Support Man/Woman Marriage, a two-page pamphlet written by a creationist economist (goes to RationalWiki). Many of the arguments presented in the pamphlet are actually religious arguments, and many others could be used as arguments against man/woman marriage. The original of this pamphlet is hosted at Phyllis Schafley’s Eagle Forum Website. (RationalWiki takes apart the seventy-seven points, showing why Gish Gallops are easy to assert and wordy to refute. They also show the implicit appeal to authority, as the writer lists her doctorate and insists on being called “Doctor” though her degree is in economics.)
Gish Gallops can be defeated in a number of ways:
a) All Gish Gallopers have a canned delivery for their firehose spray of bullshit talking points, as it takes practice and memorisation to put together a seemingly-coherent Gish Gallop. Amateur religious apologists rarely use the Gish Gallop for precisely this reason: You will most likely encounter the Gish Gallop in such things as Saturday door-knocking evangelists. One can study what that person or organisation has said in past apologetics, to prepare to deal with what will likely be the same canned delivery. Learning about your adversary in a debate through transcripts or videos of previous debates and the points your opponent will bring up is part of good preparation. Since Christian apologists who come knocking on doors pretty much use all the same talking points in their Gish Gallops, it only takes a few counter-arguments to get them to declare you “in the thrall of Satan” and go off to bother someone else.
b) Try to take those talking points and lump them into groups. Since much of a Gish Gallop is the same point restated a number of different ways, defeating the Gallop becomes much easier if you can wipe out vast swaths of the galloper’s arguments in one slug.
c) Gish Gallop points are trivial to assert but ofttimes are tedious to refute—refuting those points can cause your audience’s eyes to glaze over. As such, you can simply ask for the galloper’s best few arguments and refute those. (However, this leaves you open to the charge from an apologist that you “cherry-picked” even though the apologist provided the arguments, with the follow-up claim that his or her other arguments would have won a debate.)
d) The galloper relies on the veneer of the appeal to authority fallacy by seeming to have vast knowledge, while refuting the points of the galloper requires actual knowledge which the anti-apologist likely doesn’t have on hand for so many subjects. This refers back to a): If you know in advance what the galloper will try to do, you can bone up on the knowledge required. This is especially true of door-knocking missionaries. Since most atheists know the Bible better than religious believers, atheists can derail a Gish Gallop from a missionary fairly easily.
e) To quote the WOPR computer in the movie War Games, sometimes “the only way to win is not to play.” In that instance, simply call it what it is (a Gish Gallop) and call it a day. You’ll be open to a charge of an ad hominem attack, but the galloper doesn’t really care about the truth or that person wouldn’t use a Gish Gallop in the first place.