1
00:00:10,540 --> 00:00:17,730
We've seen what Locke has to say about personal identity.
2
00:00:17,730 --> 00:00:25,620
Admittedly, only briefly, but you can see that he distinguishes between the identity of different things,
3
00:00:25,620 --> 00:00:32,610
in particular distinguishes between the identity of a physical organism and the person.
4
00:00:32,610 --> 00:00:43,370
He's got a clear motive for doing that because of the forensic importance of the notion of person, its relation to morality and desert and so forth.
5
00:00:43,370 --> 00:00:51,650
And he links personhood with consciousness. And therefore with memory.
6
00:00:51,650 --> 00:00:58,200
Now, Thomas Reed famously raised a problem case for Locke, which he put like this.
7
00:00:58,200 --> 00:01:03,150
Suppose you've got a young lieutenant in the Army. He can remember what he did as a child.
8
00:01:03,150 --> 00:01:11,170
Maybe, for example, he can remember stealing an apple. Maybe feels guilty about it.
9
00:01:11,170 --> 00:01:19,670
When he becomes a general. The general can remember what the lieutenant did, but he can't remember what the child did.
10
00:01:19,670 --> 00:01:24,370
He's completely forgotten about the Apple incident.
11
00:01:24,370 --> 00:01:32,620
Now, if memory constitutes personal identity, then it looks like the lieutenant is the same one, I'm the same person as the child.
12
00:01:32,620 --> 00:01:40,080
The general is one and the same person as the lieutenant. But the general is not the same person as the child.
13
00:01:40,080 --> 00:01:47,020
And that seems to be a contradiction because the notion of identity is supposed to be a transitive relation.
14
00:01:47,020 --> 00:01:51,820
That is, if X is identical with Y. And why is identical with Z?
15
00:01:51,820 --> 00:01:58,110
It follows that X is identical with Z. That seems to be a logical truth about the notion of identity.
16
00:01:58,110 --> 00:02:02,770
Indeed, it follows from Lightman's law.
17
00:02:02,770 --> 00:02:10,240
Well, there is a nice, elegant way of getting around this, so we introduce what's called the ancestral relation.
18
00:02:10,240 --> 00:02:18,580
You'll see. It's obvious why it's called the ancestral relation, because the classic example of this is the relation of being an ancestor.
19
00:02:18,580 --> 00:02:25,120
So look at this definition. X is an ancestor of Y if either.
20
00:02:25,120 --> 00:02:33,540
X is a parent of Y. Or X is a parent of an ancestor of Y.
21
00:02:33,540 --> 00:02:35,820
Now, when you first see that definition, you might think.
22
00:02:35,820 --> 00:02:43,230
Isn't that a bit odd because the word ancestor is not only appearing as the word to be defined.
23
00:02:43,230 --> 00:02:50,580
It's also appearing in the definition. Isn't that circular? Well, in a sense it is, but it's not viciously circular.
24
00:02:50,580 --> 00:02:59,150
And that's because we have the first clause as well. So suppose we want to identify who my ancestors are.
25
00:02:59,150 --> 00:03:05,350
Well, what this says is, first of all, my parents are ancestors.
26
00:03:05,350 --> 00:03:13,160
Okay, but then their parents and sisters, because they have parents of ancestors of mine.
27
00:03:13,160 --> 00:03:20,610
And then their parents or ancestors of mine. Because their parents of ancestors of mine and so on.
28
00:03:20,610 --> 00:03:27,300
So actually, it's very elegant, neat way of getting a recursive definition.
29
00:03:27,300 --> 00:03:31,140
The definition van sister appeals to the notion of ancestry itself.
30
00:03:31,140 --> 00:03:37,630
So it's recursive. But it's not viciously said.
31
00:03:37,630 --> 00:03:44,610
Now, consider that in the abstract, consider what we've done, we've taken the neat notion of parent,
32
00:03:44,610 --> 00:03:54,520
the relation of being a parent, and we have generated from that a more general relation that includes parenthood.
33
00:03:54,520 --> 00:04:03,570
But as it were, iterates it. So we call ancestor the ancestral relation of parent.
34
00:04:03,570 --> 00:04:09,020
Now, suppose we do the same with memory. Suppose we say.
35
00:04:09,020 --> 00:04:17,380
That's that. Ex. Is memory continuous with why?
36
00:04:17,380 --> 00:04:25,520
If either. X can remember Y's actions or.
37
00:04:25,520 --> 00:04:32,960
X can remember the actions of someone who is memory continuous with Y.
38
00:04:32,960 --> 00:04:39,620
So now what we have is that the general is memory continuous with the child
39
00:04:39,620 --> 00:04:43,130
because the general is memory continuous with the lieutenant and the lieutenant,
40
00:04:43,130 --> 00:04:50,070
his memory continuous with the child. So we get round Reid's problem by extending Locke's account.
41
00:04:50,070 --> 00:05:03,570
We don't make it rely just on what a single step memory we allow iterated memories to count as well.
42
00:05:03,570 --> 00:05:10,550
There's another advantage of this sort of approach, which is as follows.
43
00:05:10,550 --> 00:05:21,830
My continuity with myself yesterday. We're reluctant to think that that's anything to do with whether I can remember exactly what I did yesterday.
44
00:05:21,830 --> 00:05:29,300
I mean, suppose you go to a really good party and afterwards you can remember very little of what went on.
45
00:05:29,300 --> 00:05:38,710
That doesn't mean you're not the same person. Now.
46
00:05:38,710 --> 00:05:45,370
Suppose, on the other hand, do you imagine yourself through those hours? If you if you're calm.
47
00:05:45,370 --> 00:05:48,040
I realise this may be a question in those circumstances.
48
00:05:48,040 --> 00:05:58,480
But if your consciousness is continuous throughout the period, then you cannot each moment remember what happened in the immediately previous moment.
49
00:05:58,480 --> 00:06:04,810
You have it have, as it were, a continuity of experience and the ancestral relation.
50
00:06:04,810 --> 00:06:08,880
Let you build that right through the day. So you don't lose any.
51
00:06:08,880 --> 00:06:15,970
You don't have to say that at eleven o'clock in the evening, you have to be able to remember what happened at nine o'clock in the morning.
52
00:06:15,970 --> 00:06:27,430
The continuity can come through the ancestral relation. But there are, of course, lots of problems remaining.
53
00:06:27,430 --> 00:06:37,790
One problem is so-called quasar memory. If you base personal identity on memory.
54
00:06:37,790 --> 00:06:42,830
The trouble with that is something only counts as a genuine memory if it concerns your own experiences.
55
00:06:42,830 --> 00:06:49,380
Suppose I wake up. With an apparent memory of your experiences.
56
00:06:49,380 --> 00:06:53,910
Very peculiar. But would we call that memory? No, we wouldn't.
57
00:06:53,910 --> 00:06:57,510
We'd say that isn't a genuine memory. Something's gone wrong.
58
00:06:57,510 --> 00:07:02,760
Goodness knows what. But that's not a genuine memory. OK.
59
00:07:02,760 --> 00:07:09,960
So straight off, we need to say that the what we are using as a criterion of personal identity is not genuine memory.
60
00:07:09,960 --> 00:07:12,570
It's apparent memory, quasar memory.
61
00:07:12,570 --> 00:07:18,090
If we say genuine memory, then that's just going to be circular because we're only going to count it as genuine memory.
62
00:07:18,090 --> 00:07:26,710
If the we have personal identity. Another problem.
63
00:07:26,710 --> 00:07:36,770
Sleep. Well, continuity of consciousness may do the job from morning until night.
64
00:07:36,770 --> 00:07:43,490
But what about when you go to sleep? Does your consciousness then switch off?
65
00:07:43,490 --> 00:07:45,590
Well, maybe you can get round that.
66
00:07:45,590 --> 00:07:58,700
Maybe you can say with Descartes that it's of the essence of your mind that it's always thinking, maybe sometimes thinking semi consciously.
67
00:07:58,700 --> 00:08:04,220
And maybe you're going to be able to build that into some account. You can see there's a difficulty there.
68
00:08:04,220 --> 00:08:09,000
We're not going to be able to rely on full consciousness in the way that Locke wanted to.
69
00:08:09,000 --> 00:08:14,890
But what about Koma? What if someone goes into a coma?
70
00:08:14,890 --> 00:08:23,230
Suppose for a time, brain activity ceases. We have every reason to think that there is no consciousness, whatever, over that period.
71
00:08:23,230 --> 00:08:29,950
But then it revives. Would we not want to say that it's the same person?
72
00:08:29,950 --> 00:08:39,090
Particularly if they continue to act in the same way they retain memories from before and so on?
73
00:08:39,090 --> 00:08:44,850
Well, this suggests that some element of BOTTOMLY or at least brain continuity, is desirable.
74
00:08:44,850 --> 00:08:49,240
It enables you to bridge over the gaps in these sorts of cases.
75
00:08:49,240 --> 00:08:54,890
If somebody had a really bad accident, the brain appeared to switch off for a time.
76
00:08:54,890 --> 00:09:02,000
But then switched on again and things continued more or less as normal. I'm sure we would want to say it's the same person.
77
00:09:02,000 --> 00:09:08,030
We do that because largely because it's the same physical body.
78
00:09:08,030 --> 00:09:13,700
And we assume that with the same physical body. Broadly, the same mind is there.
79
00:09:13,700 --> 00:09:17,750
It's like turning your computer off and turning it on again. It's still your computer.
80
00:09:17,750 --> 00:09:28,910
It's still got all the memories and software, etc. from before. And that might lead us to think that bodily identity is really the crucial thing.
81
00:09:28,910 --> 00:09:34,850
Consciousness doesn't matter so much. What matters most is the physical seat of consciousness.
82
00:09:34,850 --> 00:09:40,565
The thing that actually causes it.
00:00:10,540 --> 00:00:17,730
We've seen what Locke has to say about personal identity.
2
00:00:17,730 --> 00:00:25,620
Admittedly, only briefly, but you can see that he distinguishes between the identity of different things,
3
00:00:25,620 --> 00:00:32,610
in particular distinguishes between the identity of a physical organism and the person.
4
00:00:32,610 --> 00:00:43,370
He's got a clear motive for doing that because of the forensic importance of the notion of person, its relation to morality and desert and so forth.
5
00:00:43,370 --> 00:00:51,650
And he links personhood with consciousness. And therefore with memory.
6
00:00:51,650 --> 00:00:58,200
Now, Thomas Reed famously raised a problem case for Locke, which he put like this.
7
00:00:58,200 --> 00:01:03,150
Suppose you've got a young lieutenant in the Army. He can remember what he did as a child.
8
00:01:03,150 --> 00:01:11,170
Maybe, for example, he can remember stealing an apple. Maybe feels guilty about it.
9
00:01:11,170 --> 00:01:19,670
When he becomes a general. The general can remember what the lieutenant did, but he can't remember what the child did.
10
00:01:19,670 --> 00:01:24,370
He's completely forgotten about the Apple incident.
11
00:01:24,370 --> 00:01:32,620
Now, if memory constitutes personal identity, then it looks like the lieutenant is the same one, I'm the same person as the child.
12
00:01:32,620 --> 00:01:40,080
The general is one and the same person as the lieutenant. But the general is not the same person as the child.
13
00:01:40,080 --> 00:01:47,020
And that seems to be a contradiction because the notion of identity is supposed to be a transitive relation.
14
00:01:47,020 --> 00:01:51,820
That is, if X is identical with Y. And why is identical with Z?
15
00:01:51,820 --> 00:01:58,110
It follows that X is identical with Z. That seems to be a logical truth about the notion of identity.
16
00:01:58,110 --> 00:02:02,770
Indeed, it follows from Lightman's law.
17
00:02:02,770 --> 00:02:10,240
Well, there is a nice, elegant way of getting around this, so we introduce what's called the ancestral relation.
18
00:02:10,240 --> 00:02:18,580
You'll see. It's obvious why it's called the ancestral relation, because the classic example of this is the relation of being an ancestor.
19
00:02:18,580 --> 00:02:25,120
So look at this definition. X is an ancestor of Y if either.
20
00:02:25,120 --> 00:02:33,540
X is a parent of Y. Or X is a parent of an ancestor of Y.
21
00:02:33,540 --> 00:02:35,820
Now, when you first see that definition, you might think.
22
00:02:35,820 --> 00:02:43,230
Isn't that a bit odd because the word ancestor is not only appearing as the word to be defined.
23
00:02:43,230 --> 00:02:50,580
It's also appearing in the definition. Isn't that circular? Well, in a sense it is, but it's not viciously circular.
24
00:02:50,580 --> 00:02:59,150
And that's because we have the first clause as well. So suppose we want to identify who my ancestors are.
25
00:02:59,150 --> 00:03:05,350
Well, what this says is, first of all, my parents are ancestors.
26
00:03:05,350 --> 00:03:13,160
Okay, but then their parents and sisters, because they have parents of ancestors of mine.
27
00:03:13,160 --> 00:03:20,610
And then their parents or ancestors of mine. Because their parents of ancestors of mine and so on.
28
00:03:20,610 --> 00:03:27,300
So actually, it's very elegant, neat way of getting a recursive definition.
29
00:03:27,300 --> 00:03:31,140
The definition van sister appeals to the notion of ancestry itself.
30
00:03:31,140 --> 00:03:37,630
So it's recursive. But it's not viciously said.
31
00:03:37,630 --> 00:03:44,610
Now, consider that in the abstract, consider what we've done, we've taken the neat notion of parent,
32
00:03:44,610 --> 00:03:54,520
the relation of being a parent, and we have generated from that a more general relation that includes parenthood.
33
00:03:54,520 --> 00:04:03,570
But as it were, iterates it. So we call ancestor the ancestral relation of parent.
34
00:04:03,570 --> 00:04:09,020
Now, suppose we do the same with memory. Suppose we say.
35
00:04:09,020 --> 00:04:17,380
That's that. Ex. Is memory continuous with why?
36
00:04:17,380 --> 00:04:25,520
If either. X can remember Y's actions or.
37
00:04:25,520 --> 00:04:32,960
X can remember the actions of someone who is memory continuous with Y.
38
00:04:32,960 --> 00:04:39,620
So now what we have is that the general is memory continuous with the child
39
00:04:39,620 --> 00:04:43,130
because the general is memory continuous with the lieutenant and the lieutenant,
40
00:04:43,130 --> 00:04:50,070
his memory continuous with the child. So we get round Reid's problem by extending Locke's account.
41
00:04:50,070 --> 00:05:03,570
We don't make it rely just on what a single step memory we allow iterated memories to count as well.
42
00:05:03,570 --> 00:05:10,550
There's another advantage of this sort of approach, which is as follows.
43
00:05:10,550 --> 00:05:21,830
My continuity with myself yesterday. We're reluctant to think that that's anything to do with whether I can remember exactly what I did yesterday.
44
00:05:21,830 --> 00:05:29,300
I mean, suppose you go to a really good party and afterwards you can remember very little of what went on.
45
00:05:29,300 --> 00:05:38,710
That doesn't mean you're not the same person. Now.
46
00:05:38,710 --> 00:05:45,370
Suppose, on the other hand, do you imagine yourself through those hours? If you if you're calm.
47
00:05:45,370 --> 00:05:48,040
I realise this may be a question in those circumstances.
48
00:05:48,040 --> 00:05:58,480
But if your consciousness is continuous throughout the period, then you cannot each moment remember what happened in the immediately previous moment.
49
00:05:58,480 --> 00:06:04,810
You have it have, as it were, a continuity of experience and the ancestral relation.
50
00:06:04,810 --> 00:06:08,880
Let you build that right through the day. So you don't lose any.
51
00:06:08,880 --> 00:06:15,970
You don't have to say that at eleven o'clock in the evening, you have to be able to remember what happened at nine o'clock in the morning.
52
00:06:15,970 --> 00:06:27,430
The continuity can come through the ancestral relation. But there are, of course, lots of problems remaining.
53
00:06:27,430 --> 00:06:37,790
One problem is so-called quasar memory. If you base personal identity on memory.
54
00:06:37,790 --> 00:06:42,830
The trouble with that is something only counts as a genuine memory if it concerns your own experiences.
55
00:06:42,830 --> 00:06:49,380
Suppose I wake up. With an apparent memory of your experiences.
56
00:06:49,380 --> 00:06:53,910
Very peculiar. But would we call that memory? No, we wouldn't.
57
00:06:53,910 --> 00:06:57,510
We'd say that isn't a genuine memory. Something's gone wrong.
58
00:06:57,510 --> 00:07:02,760
Goodness knows what. But that's not a genuine memory. OK.
59
00:07:02,760 --> 00:07:09,960
So straight off, we need to say that the what we are using as a criterion of personal identity is not genuine memory.
60
00:07:09,960 --> 00:07:12,570
It's apparent memory, quasar memory.
61
00:07:12,570 --> 00:07:18,090
If we say genuine memory, then that's just going to be circular because we're only going to count it as genuine memory.
62
00:07:18,090 --> 00:07:26,710
If the we have personal identity. Another problem.
63
00:07:26,710 --> 00:07:36,770
Sleep. Well, continuity of consciousness may do the job from morning until night.
64
00:07:36,770 --> 00:07:43,490
But what about when you go to sleep? Does your consciousness then switch off?
65
00:07:43,490 --> 00:07:45,590
Well, maybe you can get round that.
66
00:07:45,590 --> 00:07:58,700
Maybe you can say with Descartes that it's of the essence of your mind that it's always thinking, maybe sometimes thinking semi consciously.
67
00:07:58,700 --> 00:08:04,220
And maybe you're going to be able to build that into some account. You can see there's a difficulty there.
68
00:08:04,220 --> 00:08:09,000
We're not going to be able to rely on full consciousness in the way that Locke wanted to.
69
00:08:09,000 --> 00:08:14,890
But what about Koma? What if someone goes into a coma?
70
00:08:14,890 --> 00:08:23,230
Suppose for a time, brain activity ceases. We have every reason to think that there is no consciousness, whatever, over that period.
71
00:08:23,230 --> 00:08:29,950
But then it revives. Would we not want to say that it's the same person?
72
00:08:29,950 --> 00:08:39,090
Particularly if they continue to act in the same way they retain memories from before and so on?
73
00:08:39,090 --> 00:08:44,850
Well, this suggests that some element of BOTTOMLY or at least brain continuity, is desirable.
74
00:08:44,850 --> 00:08:49,240
It enables you to bridge over the gaps in these sorts of cases.
75
00:08:49,240 --> 00:08:54,890
If somebody had a really bad accident, the brain appeared to switch off for a time.
76
00:08:54,890 --> 00:09:02,000
But then switched on again and things continued more or less as normal. I'm sure we would want to say it's the same person.
77
00:09:02,000 --> 00:09:08,030
We do that because largely because it's the same physical body.
78
00:09:08,030 --> 00:09:13,700
And we assume that with the same physical body. Broadly, the same mind is there.
79
00:09:13,700 --> 00:09:17,750
It's like turning your computer off and turning it on again. It's still your computer.
80
00:09:17,750 --> 00:09:28,910
It's still got all the memories and software, etc. from before. And that might lead us to think that bodily identity is really the crucial thing.
81
00:09:28,910 --> 00:09:34,850
Consciousness doesn't matter so much. What matters most is the physical seat of consciousness.
82
00:09:34,850 --> 00:09:40,565
The thing that actually causes it.
