0:05 [Music]
0:07 hello everyone and welcome back to
0:10 another a lecture on semantics our topic
0:13 for today is theories of concepts if you
0:15 recall from our previous lecture we
0:18 discussed the semiotic triangle we also
0:21 discussed under the notion of reference
0:24 that there were two theories a reference
0:26 one was the notational Theory in the
0:28 other was the representational theory
0:30 the representational theory suggests
0:32 that the word or linguistic expression
0:36 means a sense or a concept a mental
0:38 representation that we have in our minds
0:41 our task for today is to identify or
0:44 understand in greater detail what this
0:47 concept is now there are several
0:49 theories that talk about what the
0:52 concept is what it contains that will be
0:55 our topic for today stay tuned so when
0:57 it comes identifying what a concept is
1:00 there are four major theories first is
1:03 the image theory second we will discuss
1:06 it called the classical theory third we
1:09 will discuss is called the causal theory
1:11 and the fourth one we will discuss is
1:14 called the prototype theory let's begin
1:17 with the first one the image theory now
1:19 the image theory is quite simple in its
1:21 tenets basically what that image theory
1:23 suggests that when a linguistic
1:26 expression is utter say the word dog the
1:30 concept we think of is an actual image
1:33 say this image for instance and of
1:35 course you know the rest it is this
1:37 image that helps us determine which
1:40 object in the world is an instance of
1:42 dog but of course right away you can see
1:44 some of the problems that can arise from
1:49 taking our concept or our sense of the
1:53 word dog to be an actual image so right
1:55 off the bat you can imagine that people
1:57 will have different images in their
2:00 minds about what constitutes a dog what
2:03 is a dog is it something like his
2:07 picture or like this or this or even
2:11 this not only that but if we were all to
2:13 agree on the first one
2:15 on this picture that this is what
2:18 represents a dot then how are we to say
2:21 that this is also a dog when it doesn't
2:24 look very much like the first picture if
2:25 we were to take the image theory and
2:28 even in the best case scenario where we
2:32 were to agree on one image for dog it
2:34 will be very difficult to include other
2:38 types of dogs into the category dog this
2:40 theory then clearly has its shortcomings
2:43 so let's put this theory aside for now
2:45 we'll start now with the classical
2:47 theory now the classical theory has
2:49 another name for it which is the
2:53 necessary and sufficient conditions
2:55 theory what do we mean by the necessary
2:58 and sufficient conditions well under
3:00 this classical theory when we say the
3:04 word dog the sense in our minds of the
3:07 word dog is not an image like the image
3:10 theory but rather a list of conditions
3:14 that the dog must meet in order to be an
3:20 actual dog in the real world this list
3:22 of conditions may be something like this
3:28 a dog must be plus animal plus four legs
3:33 - gills for example that it doesn't
3:34 breathe underwater
3:36 okay so this is just an example but
3:38 that's basically how it would go and
3:41 then every time you say the word dog and
3:44 you want to identify if this word you
3:46 notice the actual dog you see in the
3:49 real world you will use this list of
3:52 necessary and sufficient conditions to
3:54 determine whether what you see in the
3:57 real world is a dog or not is it a
4:00 member of the category dog or not this
4:02 is going to be based on these conditions
4:04 again we can still see some problems
4:06 though even with the necessary in the
4:08 sufficient conditions theory or the
4:10 classical theory and that is that people
4:15 do not tend to agree upon all of the
4:17 necessary and sufficient conditions the
4:21 second problem is that how much of these
4:24 necessary and sufficient conditions must
4:25 we agree upon in order
4:27 to understand each other these things
4:29 are not clear take for example the word
4:32 gold what can gold denote in the real
4:35 world well we're gonna have to have the
4:37 meaning of gold for the imitation of
4:41 gold being mediated by our concept but
4:41 here's the thing
4:44 this concept is going to be different
4:46 for each and every speaker so for an
4:50 ordinary person gold might be plus metal
4:56 plus expensive plus yellowish and plus
4:58 shiny now I'm sure a lot of things in
5:01 the world fit this description how come
5:04 we still are able to understand what
5:07 gold is not only that but a person
5:10 mining for gold or a chemist might have
5:12 a different idea of what gold is so
5:16 scientists might think of gold's density
5:20 or the number of atoms or if it could be
5:24 bent and shaped or not they surely won't
5:26 be taking our simple definition of
5:28 something goal of something of a gold
5:32 color and shiny so really the main
5:35 problem with the classical theory is
5:39 that there's no room for fuzziness what
5:41 do we mean by fuzziness we mean that
5:45 sometimes it's not very clear or a
5:48 clear-cut distinction between either you
5:50 are part of this category or not
5:52 sometimes things are in a gray area and
5:55 we are still able to understand it this
5:57 theory looks at things in a more like a
6:01 0 or 1 relationship you're either an
6:04 instance of something or you're not for
6:07 example plus think up the category bird
6:09 now the category bird under the
6:11 necessary and sufficient conditions
6:17 could be + animal loss fly that I can
6:21 fly plus feathers right so these are the
6:22 basic things we think of when we think
6:26 of bird now think of a canary is a
6:28 canary a good example of bird is it a
6:30 bird under this definition well yes it's
6:33 an animal check it can fly it has
6:37 feathers but what about a chicken well
6:38 the chickens an animal
6:41 feathers but it doesn't fly under the
6:42 necessary and sufficient conditions
6:45 theory or the classical theory chicken
6:48 is not a bird what about penguin the
6:51 penguin is an animal but it doesn't have
6:54 feathers but they do not fly actually
6:58 penguins swim they're actually very good
7:01 swimmers so again under this theory
7:05 penguins are not birds so you can see
7:08 there that fuzziness or accepting fuzzy
7:10 members is a real problem for the
7:12 classical theory let's move on to the
7:13 next one
7:15 so now we can throw the classical theory
7:18 out the window as well stay tuned for
7:20 our next lecture in which we're going to
7:22 discuss the causal theory and the
7:26 prototype theory see you there you
