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Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.51,0:00:06.61,Default,,0000,0000,0000,,[ Music ]
Dialogue: 0,0:00:07.11,0:00:11.17,Default,,0000,0000,0000,,>> Hello. I'm Paul Henne, and I'm a\Nphilosophy gradate student at Duke University.
Dialogue: 0,0:00:11.65,0:00:16.37,Default,,0000,0000,0000,,And in this video, I'm going to introduce\Nyou to formal and informal fallacies.
Dialogue: 0,0:00:16.99,0:00:19.36,Default,,0000,0000,0000,,First, consider the following arguments.
Dialogue: 0,0:00:19.89,0:00:24.41,Default,,0000,0000,0000,,Premise one: if someone is allergic to\Npeanuts, then she doesn't eat peanut butter.
Dialogue: 0,0:00:24.86,0:00:27.27,Default,,0000,0000,0000,,Premise two: Jane doesn't eat peanut butter.
Dialogue: 0,0:00:27.61,0:00:30.53,Default,,0000,0000,0000,,Conclusion: therefore Jane\Nis allergic to peanuts.
Dialogue: 0,0:00:31.45,0:00:32.60,Default,,0000,0000,0000,,Consider this other argument.
Dialogue: 0,0:00:33.21,0:00:35.54,Default,,0000,0000,0000,,Premise one: a feather is light.
Dialogue: 0,0:00:36.15,0:00:38.65,Default,,0000,0000,0000,,Premise two: what's light cannot be dark.
Dialogue: 0,0:00:39.03,0:00:42.47,Default,,0000,0000,0000,,Conclusion: therefore a feather cannot be dark.
Dialogue: 0,0:00:43.56,0:00:46.77,Default,,0000,0000,0000,,These arguments probably seemed a\Nbit off to you, and you're right.
Dialogue: 0,0:00:47.24,0:00:51.12,Default,,0000,0000,0000,,Each argument contains a fallacy,\Nthough each has a different kind.
Dialogue: 0,0:00:51.87,0:00:57.11,Default,,0000,0000,0000,,A fallacy, as we've seen in other wireless\Nphilosophy videos, is a defect in reasoning.
Dialogue: 0,0:00:57.52,0:01:01.08,Default,,0000,0000,0000,,This defect can be unintentional or intentional.
Dialogue: 0,0:01:01.49,0:01:05.16,Default,,0000,0000,0000,,That is, I could simply make\Na mistake in my reasoning.
Dialogue: 0,0:01:05.46,0:01:09.30,Default,,0000,0000,0000,,Or I could want to trick you into believing\Nsomething by using deceptive reasoning.
Dialogue: 0,0:01:10.37,0:01:14.28,Default,,0000,0000,0000,,Either way, it's probably a good\Nidea that we are able to understand
Dialogue: 0,0:01:14.28,0:01:16.86,Default,,0000,0000,0000,,and identify distinct fallacy types
Dialogue: 0,0:01:17.10,0:01:20.85,Default,,0000,0000,0000,,so that we can adequately correct\Nany defects in our reasoning.
Dialogue: 0,0:01:22.01,0:01:27.46,Default,,0000,0000,0000,,But before we talk about fallacy types,\Nlet's recall what a valid argument is.
Dialogue: 0,0:01:28.14,0:01:29.21,Default,,0000,0000,0000,,Consider this argument.
Dialogue: 0,0:01:29.55,0:01:34.71,Default,,0000,0000,0000,,Premise one: if someone is a philosopher,\Nthen she publishes articles on philosophy.
Dialogue: 0,0:01:34.87,0:01:41.03,Default,,0000,0000,0000,,So Tamar Gendler is a philosopher, therefore,\NTamar Gendler publishes articles in philosophy.
Dialogue: 0,0:01:42.14,0:01:43.17,Default,,0000,0000,0000,,This is a valid argument.
Dialogue: 0,0:01:43.81,0:01:47.94,Default,,0000,0000,0000,,Actually, although it isn't bearing on this\Nargument's validity, Gendler has published
Dialogue: 0,0:01:47.94,0:01:50.36,Default,,0000,0000,0000,,over 20 articles, among her other works.
Dialogue: 0,0:01:51.05,0:01:56.64,Default,,0000,0000,0000,,This form of argument is called modus ponens,\Nand it can be represented as the following.
Dialogue: 0,0:01:57.25,0:02:03.89,Default,,0000,0000,0000,,Premise one: if X, then Y. Premise\Ntwo: X. Conclusion: therefore Y.
Dialogue: 0,0:02:04.53,0:02:07.29,Default,,0000,0000,0000,,And this is a valid argument form.
Dialogue: 0,0:02:07.68,0:02:11.02,Default,,0000,0000,0000,,The conclusion necessarily\Nfollows from the premises.
Dialogue: 0,0:02:11.71,0:02:16.09,Default,,0000,0000,0000,,Remember though, this valid form does\Nnot mean that the premises are true.
Dialogue: 0,0:02:16.59,0:02:21.25,Default,,0000,0000,0000,,It would still be a valid argument if Tamar\NGendler had decided to become a train conductor,
Dialogue: 0,0:02:21.25,0:02:23.01,Default,,0000,0000,0000,,for instance, instead of a philosopher.
Dialogue: 0,0:02:23.23,0:02:28.39,Default,,0000,0000,0000,,See the videos on soundness and validity\Nif you have questions about this.
Dialogue: 0,0:02:30.39,0:02:33.02,Default,,0000,0000,0000,,We can also have an invalid argument form.
Dialogue: 0,0:02:33.59,0:02:35.23,Default,,0000,0000,0000,,Let's return to our first argument.
Dialogue: 0,0:02:36.25,0:02:41.55,Default,,0000,0000,0000,,This argument, as you might have suspected,\Ncontains a fallacy, a formal fallacy.
Dialogue: 0,0:02:42.04,0:02:48.23,Default,,0000,0000,0000,,And a formal fallacy is exactly what it sounds\Nlike: a defect in the form of the argument.
Dialogue: 0,0:02:49.03,0:02:53.26,Default,,0000,0000,0000,,In other words, there are certain\Nforms of arguments that are invalid.
Dialogue: 0,0:02:54.84,0:02:59.75,Default,,0000,0000,0000,,This invalid argument form is a formal\Nfallacy called affirming the consequent.
Dialogue: 0,0:03:00.66,0:03:05.51,Default,,0000,0000,0000,,This fallacy is apparent if you consider\Nthat Jane just might not like peanut butter.
Dialogue: 0,0:03:05.100,0:03:09.83,Default,,0000,0000,0000,,So simply because Jane doesn't like\Npeanut butter, she doesn't eat it.
Dialogue: 0,0:03:10.54,0:03:15.98,Default,,0000,0000,0000,,Given just the fact that she doesn't eat it and\Nthe condition in premise one, we cannot conclude
Dialogue: 0,0:03:15.98,0:03:17.67,Default,,0000,0000,0000,,that Jane is allergic to peanut butter.
Dialogue: 0,0:03:18.77,0:03:21.85,Default,,0000,0000,0000,,This form of fallacy can be\Nrepresented in the following way.
Dialogue: 0,0:03:22.75,0:03:31.81,Default,,0000,0000,0000,,If X, then Y. Y, therefore X. And this form\Nof fallacy is one that you don't want to use.
Dialogue: 0,0:03:32.06,0:03:35.67,Default,,0000,0000,0000,,It's actually one of the fallacies\Nfrequently tested on the LSAT.
Dialogue: 0,0:03:36.14,0:03:40.16,Default,,0000,0000,0000,,So if you're interested and want more\Npractice in identifying this fallacy,
Dialogue: 0,0:03:40.62,0:03:43.04,Default,,0000,0000,0000,,check out the video on affirming the consequent.
Dialogue: 0,0:03:44.47,0:03:48.73,Default,,0000,0000,0000,,We will talk more about this and other\Nformal fallacies in upcoming videos.
Dialogue: 0,0:03:48.99,0:03:53.75,Default,,0000,0000,0000,,But for now, we need to see that\Nformal fallacies are fallacies
Dialogue: 0,0:03:54.13,0:03:56.41,Default,,0000,0000,0000,,because of the poor form of the argument.
Dialogue: 0,0:03:57.50,0:04:00.75,Default,,0000,0000,0000,,Any argument of these forms will be invalid.
Dialogue: 0,0:04:01.55,0:04:05.17,Default,,0000,0000,0000,,So anything can be plugged\Ninto these bad argument forms
Dialogue: 0,0:04:05.56,0:04:06.91,Default,,0000,0000,0000,,and the argument would be invalid.
Dialogue: 0,0:04:07.38,0:04:10.52,Default,,0000,0000,0000,,For instance, if meow, then splat.
Dialogue: 0,0:04:11.08,0:04:13.94,Default,,0000,0000,0000,,Splat, therefore meow, is invalid.
Dialogue: 0,0:04:15.63,0:04:21.95,Default,,0000,0000,0000,,So now that we have a general understanding\Nof formal fallacies, what about informal ones?
Dialogue: 0,0:04:21.95,0:04:25.49,Default,,0000,0000,0000,,Lt's look at our other example\Nfrom the beginning of this video.
Dialogue: 0,0:04:26.63,0:04:31.69,Default,,0000,0000,0000,,Notice that this fallacy arises out of the\Ncontent of the argument, not out of the form.
Dialogue: 0,0:04:32.16,0:04:35.22,Default,,0000,0000,0000,,The form may at first glance seem valid.
Dialogue: 0,0:04:35.46,0:04:38.25,Default,,0000,0000,0000,,That is if we ignored the\Nmeaning of the content.
Dialogue: 0,0:04:39.11,0:04:44.49,Default,,0000,0000,0000,,Consider that we can use a seemingly similar\Nargument form to make a valid argument.
Dialogue: 0,0:04:45.02,0:04:48.11,Default,,0000,0000,0000,,For instance, premise one: rain is wet.
Dialogue: 0,0:04:48.73,0:04:51.16,Default,,0000,0000,0000,,Premise two: what's wet cannot be dry.
Dialogue: 0,0:04:51.62,0:04:54.55,Default,,0000,0000,0000,,Conclusion: therefore rain cannot be dry.
Dialogue: 0,0:04:54.92,0:05:00.64,Default,,0000,0000,0000,,And here we have a valid argument that seems\Nto have a similar form as the fallacious one,
Dialogue: 0,0:05:01.27,0:05:04.22,Default,,0000,0000,0000,,and one that lacks defects in its content.
Dialogue: 0,0:05:04.50,0:05:10.43,Default,,0000,0000,0000,,But the content of our fallacious\Nargument, given the two meanings of light --
Dialogue: 0,0:05:10.92,0:05:14.98,Default,,0000,0000,0000,,lightweight and light color\N-- yields some problems.
Dialogue: 0,0:05:15.17,0:05:19.64,Default,,0000,0000,0000,,That is, if we understand the meaning of\Nthe terms -- the two meanings of light,
Dialogue: 0,0:05:19.64,0:05:24.59,Default,,0000,0000,0000,,for instance -- we realize that the argument\Nactually has an invalid argument form.
Dialogue: 0,0:05:25.69,0:05:29.45,Default,,0000,0000,0000,,Initially, without considering the meaning\Nof the content, it looks like the form
Dialogue: 0,0:05:29.45,0:05:40.08,Default,,0000,0000,0000,,of the argument is something like, all X are\NY. What is Y cannot be Z. Therefore no X are Z.
Dialogue: 0,0:05:40.86,0:05:45.64,Default,,0000,0000,0000,,But actually, given the shifting\Nmeaning of light, the form is more like,
Dialogue: 0,0:05:46.32,0:05:56.35,Default,,0000,0000,0000,,all X are Y. What is W cannot be Z. Therefore\Nno X are Z. This fallacy is called equivocation.
Dialogue: 0,0:05:57.09,0:06:00.13,Default,,0000,0000,0000,,And see the video on this if\Nyou'd like to know more about it.
Dialogue: 0,0:06:01.55,0:06:07.07,Default,,0000,0000,0000,,The only way we can understand this defect\Nis by examining the content of the argument.
Dialogue: 0,0:06:07.59,0:06:10.90,Default,,0000,0000,0000,,If we just looked at the form\Nwithout understanding the content,
Dialogue: 0,0:06:11.30,0:06:13.58,Default,,0000,0000,0000,,then we could not detect this fallacy.
Dialogue: 0,0:06:14.88,0:06:18.99,Default,,0000,0000,0000,,So as we now know, informal\Nfallacies occur because of problems
Dialogue: 0,0:06:18.99,0:06:20.96,Default,,0000,0000,0000,,with the content of the arguments.
Dialogue: 0,0:06:22.13,0:06:27.11,Default,,0000,0000,0000,,So an argument might have a seemingly\Nvalid form but commit an informal fallacy
Dialogue: 0,0:06:27.11,0:06:29.01,Default,,0000,0000,0000,,because of a defect in its content.
Dialogue: 0,0:06:29.69,0:06:32.09,Default,,0000,0000,0000,,Hence, an argument might have true premises
Dialogue: 0,0:06:32.09,0:06:36.83,Default,,0000,0000,0000,,and a seemingly valid form,\Nyet also commit a fallacy.
Dialogue: 0,0:06:38.29,0:06:42.87,Default,,0000,0000,0000,,To reiterate, a formal fallacy means that\Nthe argument has a defect in its form,
Dialogue: 0,0:06:43.40,0:06:47.22,Default,,0000,0000,0000,,while an informal fallacy has a\Ndefect in the argument's content.
Dialogue: 0,0:06:47.54,0:06:50.24,Default,,0000,0000,0000,,Which might also yield a defect in its form.
Dialogue: 0,0:06:50.81,0:06:54.51,Default,,0000,0000,0000,,So now that's the difference between\Nformal and informal fallacies.