WEBVTT 00:07.590 --> 00:08.910 OK, welcome back. 00:09.930 --> 00:15.870 So now we're going to go through the three different theories that are talked about in the overview 00:15.870 --> 00:22.620 section about concepts are about and for each theory, I'm going to show you the highlights, what the 00:22.620 --> 00:23.430 theories about. 00:23.430 --> 00:27.330 And I'm going to run through a couple of problems for that particular theory. 00:27.840 --> 00:32.970 In the end, when we were wrapping up and also talk about the fourth theory, I will also look into 00:32.970 --> 00:36.180 possible ways to overcome the problems for the different theories. 00:37.140 --> 00:37.550 Right. 00:37.800 --> 00:38.850 So classical theory. 00:39.240 --> 00:43.980 So this is a theory that's been around for maybe 2500 years. 00:43.980 --> 00:49.550 At least people like Plato or Aristotle, they hold similar views to this. 00:50.490 --> 00:58.320 So according to the classical theory concept, C has definitional structure in that it is composed of 00:58.710 --> 01:06.390 a simpler concepts that express necessary and sufficient conditions for falling under the concept. 01:06.400 --> 01:09.860 C. So this is a very common example. 01:10.290 --> 01:14.960 So we have a bachelor and a bachelor is defined as a man that is unmarried. 01:15.360 --> 01:17.880 So that's the two simpler concepts. 01:18.330 --> 01:24.150 And bachelor is necessary both for man and unmarried. 01:24.480 --> 01:31.660 And if it is a man and unmarried, if you're a man and you're unmarried, then you're also that's the 01:32.070 --> 01:34.590 sufficient conditions for being a bachelor. 01:35.130 --> 01:35.550 Right? 01:35.800 --> 01:37.800 Simple, maybe. 01:39.240 --> 01:45.840 So when you're then trying to categorize objects into concept C, according to the classical theory, 01:46.830 --> 01:50.760 that's a psychological process where a concept is matched to an item. 01:50.970 --> 01:56.640 If each and every one of the concepts definitional constituents, and that's the kind of the same concept 01:57.660 --> 01:58.710 applies to the target. 01:59.130 --> 02:07.050 So again, if we take the bachelor example, we have a set of people and some of them a man, some of 02:07.080 --> 02:07.650 them a woman, 02:10.620 --> 02:12.690 and some of them are unmarried. 02:13.740 --> 02:19.050 And hence this subset who's both unmarried and men are bachelor. 02:19.260 --> 02:19.640 Right. 02:20.010 --> 02:27.390 So the different items that we looked at in this specific case, two people were both men and unmarried 02:27.390 --> 02:28.390 and has the word bachelor. 02:28.410 --> 02:31.840 Yeah, I think you see, this is a very simple way of looking at it. 02:33.330 --> 02:41.700 However, there are very many problems with this very simplified view on what a concept is about. 02:42.720 --> 02:45.450 So let's run through the most obvious ones. 02:46.890 --> 02:51.700 The first one is actually called the Plato's Problem, and it goes like this. 02:51.930 --> 02:58.620 So this is an example that Foder Lawrence and gargoyles have described as I'm using their example here. 02:59.580 --> 03:08.010 So let's say that you would like to define what paint is about the verb to paint. 03:09.480 --> 03:18.690 And I think you all have a gut feeling what you think painting is about and what the word paint is about. 03:19.230 --> 03:21.760 But let's see if you have that after this as well. 03:22.620 --> 03:30.000 So the idea of pleaders problem is that even the simplest concepts are very hard to define very clearly. 03:30.300 --> 03:38.850 You will always find counterexamples that you can use that cannot break this binary idea that it's either 03:39.030 --> 03:41.190 falling under the sea or not falling on the sea. 03:44.100 --> 03:48.250 So let's take it in a couple of steps here to paint or not to paint. 03:48.840 --> 03:53.790 So the verb to paint can be classically defined as Excalibur's why with paint. 03:54.840 --> 03:55.250 Right. 03:57.030 --> 03:59.730 So someone is covering something with paint. 04:01.530 --> 04:01.860 Good. 04:03.840 --> 04:09.330 But does this actually provide sufficient conditions for something falling under the concept? 04:10.230 --> 04:17.490 That's the question, because if the concept, the the classical theory holds, then the definition 04:17.640 --> 04:21.330 should be hold both sufficient and necessary conditions. 04:22.110 --> 04:22.470 Right. 04:24.030 --> 04:28.400 So let's take this first, try to see if we can do that. 04:29.190 --> 04:33.810 So a paint factory X explodes and hence cover spectators Y would paint. 04:35.370 --> 04:37.530 Will you then say that X have painted Y? 04:41.460 --> 04:44.430 Hmmm, maybe so that's bull case, right? 04:45.000 --> 04:48.780 I would probably not say that the factory have painted the spectators. 04:50.610 --> 04:54.150 OK, so let's say that we then need to add something to the definition. 04:54.150 --> 04:59.220 So we need to add that X needs to be an agent and Y needs to be a surface of some kind. 04:59.610 --> 05:02.890 OK, so second try then 05:05.850 --> 05:07.920 you and you are an agent, right? 05:08.460 --> 05:11.400 Kicks over a bucket of paint over your new shoes. 05:12.330 --> 05:14.430 Would you then say that you have painted your shoes? 05:17.010 --> 05:20.140 Again, that is a tricky situation, right? 05:21.480 --> 05:26.520 So would you say that you paint your shoes if you accidentally kick a bucket over them and bucket of 05:26.520 --> 05:26.850 paint? 05:27.960 --> 05:28.720 Probably not. 05:30.120 --> 05:35.450 So we need to have something more to do to the definition here of a concept to paint. 05:35.730 --> 05:42.180 So we need to add that the agent should cover the surface intentionally is just not happening something 05:42.180 --> 05:44.250 that happens as an accident. 05:44.580 --> 05:46.440 But it needs to be done intentionally. 05:46.800 --> 05:47.160 Right. 05:47.790 --> 05:48.390 So try. 05:49.950 --> 05:54.410 Michelangelo wasn't painting the ceiling of the Sistine Chapel. 05:54.750 --> 05:57.300 He was painting a picture on the ceiling. 05:58.510 --> 06:00.900 And it's a subtle difference here, isn't it? 06:02.550 --> 06:04.560 So it was not there just to paint the ceiling. 06:04.590 --> 06:06.420 He was actually there to paint a painting. 06:06.630 --> 06:07.050 Right. 06:07.260 --> 06:09.540 And that happened to be on the ceiling. 06:09.990 --> 06:11.790 But was he then painting the ceiling? 06:17.080 --> 06:22.360 So this is true, even though he was intentionally cover the ceiling with paint, so he was doing that, 06:22.450 --> 06:25.300 but he wasn't painting the ceiling was painting this picture. 06:25.450 --> 06:25.850 Right. 06:26.200 --> 06:29.920 That's probably how are you going to use how he would use the term in language. 06:31.120 --> 06:37.000 So we need to take into account that the primary intention of the agent and not just any intention, 06:37.000 --> 06:40.380 must be to paint this particular surface. 06:40.840 --> 06:49.720 So the primary intention should be to actually paint it and not just on a secondary intention, so forth, 06:49.720 --> 06:50.220 try them. 06:50.980 --> 06:56.350 So let's say again that Michelle Langley does have a primary intention to dip the tip of the paintbrush 06:56.350 --> 06:58.480 in the paint when painting this picture. 06:58.960 --> 06:59.470 Right. 07:00.160 --> 07:06.540 Does that mean that Michelle Langley had Michelangelo have just painted the paint brush that is also 07:06.550 --> 07:07.250 surface, right? 07:09.160 --> 07:09.900 Probably not. 07:10.840 --> 07:13.870 So again and again, I think you can go on for a fifth. 07:13.870 --> 07:14.560 Try on the sixth. 07:14.560 --> 07:15.310 Try in the seventh. 07:15.310 --> 07:15.590 Right. 07:15.820 --> 07:18.460 You can always find counterexamples. 07:18.880 --> 07:25.600 Were you find all kind of holes in this definition and you tried to patch them in by just adding more 07:25.600 --> 07:26.770 and more and more definition. 07:27.340 --> 07:29.930 But it's very hard to see if you can ever find the rock bottom. 07:32.200 --> 07:36.970 So that's the play those problems and have she has painted our fingers, right? 07:37.510 --> 07:39.080 Or maybe, maybe not probably them. 07:39.880 --> 07:42.360 So that's one problem with the classical theory concept. 07:42.670 --> 07:46.600 And let's look at the slightly different one, which is a little bit related. 07:48.460 --> 07:49.530 So we have this penguin. 07:51.580 --> 07:52.720 So this is a famous quote. 07:53.290 --> 07:55.930 What kind of a bird are you if you cannot fly? 07:55.930 --> 07:57.700 Said the little bird to the duck. 07:58.720 --> 08:00.130 What kind of a bird are you? 08:00.280 --> 08:03.310 If you cannot swim, send it, said the duck, and died. 08:05.860 --> 08:10.630 So what we're trying to point out here is what is called the topicality effect. 08:12.550 --> 08:19.000 So it seems to be that we rank items with respect to how typical they are as members of a category. 08:20.620 --> 08:27.310 But again, if you go back to the original classical definition, it doesn't say anything about something 08:27.310 --> 08:29.260 that is more typical than another thing. 08:29.920 --> 08:34.750 So he says if you fulfill all the conditions, then he will fall under sea. 08:35.470 --> 08:36.540 Not you will not. 08:36.640 --> 08:38.170 You will do it more or less. 08:39.220 --> 08:41.430 It's a binary definition, right? 08:42.700 --> 08:48.730 But it seems to be when we are thinking about birds, we tend to think that this dove is more like a 08:48.730 --> 08:52.360 bird than a penguin or an ostrich. 08:53.420 --> 08:56.920 I think that is how we generally think about the concept of being a bird. 08:58.030 --> 09:01.240 And that makes us a little bit more problematic as well. 09:01.450 --> 09:08.530 Because if you then say, according to classical theory of concept study birds, that one of the other 09:08.530 --> 09:13.570 things that birds must be able to do is to fly than they are in bird. 09:14.470 --> 09:17.900 But we know they are because they lay eggs and so on and so on and so on. 09:20.050 --> 09:27.280 So this is what the typical artifact is about, is there the classical theory says nothing about more 09:27.280 --> 09:29.530 or less necessarily sufficient conditions. 09:33.280 --> 09:33.580 Good. 09:34.270 --> 09:41.090 That was the classical theory concepts and the problems related to the classical theory concepts. 09:42.760 --> 09:47.740 So now we're going to talk about the prototype theory concept, which has been kind of an answer to 09:47.740 --> 09:51.310 the classical theory concept, but it's dated much, much later. 09:51.310 --> 09:54.910 So that's actually 20th century stuff. 09:55.660 --> 09:57.190 Good to see you there by.