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PART I
Consciousness
History and Background Metaphysics
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1
CONSCIOUSNESS, PERSONAL IDENTITY, AND IMMORTALITY
Amy Kind
Introduction
Several different intersecting questions are in play in philosophical discussions of personal identity. One such question concerns the nature of persons: What makes someone a person? Another question concerns the nature of self-identification: What makes someone the particular person that she is? And yet a third question concerns the nature of a person’s existence through time: What makes a person the same person over time?1
In this chapter we focus primarily on the third question and, in particular, the role that consciousness has played in philosophical attempts to answer it. We begin in Section 1 with the memory-based view of personal identity offered by John Locke. Though this view faces various objections, we turn in Section 2 to various adjustments that can be made to the view to make it considerably more plausible. In Section 3 we turn away from these psychologically-based approaches to physical alternatives. Finally, in Section 4, we turn to a consideration of how issues related to immortality help shed light on the debate about personal identity.
1 The Lockean View
John Locke (1632–1704) is often considered the father of philosophical discussion of personal identity. In his Essay Concerning Human Understanding he offered an account of personal identity over time that has proved particularly influential:
since consciousness always accompanies thinking, and it is that which makes every one to be what he calls self, and thereby distinguishes himself from all other thinking things, in this alone consists personal Identity, i.e. the sameness of a rational being: And as far as this consciousness can be extended backwards to any past Action or Thought, so far reaches the Identity of that Person; it is the same self now as it was then; and ’tis by the same self with this present one that now reflects on it, that that Action was done.
(Locke 1689/1975: 335)
In talking about extending one’s consciousness backward, Locke seems to have memory in mind. In particular, it seems that he is here focusing on what is often called episodic or experience memory. Episodic memory involves memories of events that were personally experienced, and it thereby contrasts with purely factual memory. When taking a geography test you’re likely to be relying primarily on your factual memories – all those state capitals and river names that you’ve previously memorized. In contrast, when writing your autobiography you’re likely to be relying primarily on your episodic memories – all those life experiences that you’ve previously undergone.
With this distinction in place, we can see why episodic memory might naturally be described as a backward extension of consciousness. We can also see why episodic memory might naturally be invoked to explain personal identity over time. It seems plausible that we’re each connected to our past selves by our episodic memories of those selves’ experiences. Consider an example. On November 2, 2004, someone was elected as the United States senator representing Illinois. On January 20, 1999, someone was sworn in as the 44th President of the United States. And on January 13, 2016, someone gave a State of the Union address. What makes it the case that each of these three “someones” is the very same person, the person known as Barack Obama? According to Locke’s theory, it’s due to the fact that they share the very same consciousness. The person giving the State of the Union address can remember being sworn in as President, and can remember being elected as the senator from Illinois, and it’s in these connections of episodic memory – in the sharing of consciousness – that personal identity consists.
Of course, in an ordinary case like this one, not only do the three someones share the same consciousness but they also share the same body. So we might wonder why a theorist like Locke would privilege sameness of consciousness over sameness of body in accounting for personal identity. Here it’s perhaps most helpful to consider hypothetical cases in which sameness of consciousness and sameness of body come apart. Many such cases are presented to us in fiction and film, and they tend to involve the transfer of consciousness from one human body to another (or from one human body to some other kind of body altogether). In thinking about these cases, it may be helpful to keep in mind an analogy used by Locke: Just as we wouldn’t think that someone becomes a different person by changing their clothes, we also shouldn’t think that someone becomes a different person just by changing their bodies.
Take Freaky Friday, for example – be it the 1972 book by Mary Rodgers or any of the various film versions. Though the details vary somewhat from book to film to remake, the basic body swap plotline remains the same across all the different versions. Let’s consider the 2003 film starring Lindsay Lohan as a teenage girl named Anna and Jamie Lee Curtis as Anna’s mother Tess. One morning, after having received cryptic fortunes while out for dinner the night before, Tess and Anna awake to discover that Tess’s consciousness is now in Anna’s body, and Anna’s consciousness is now in Tess’s body. As the plot unfolds, it’s clear that viewers are meant to think that each of the characters goes where her consciousness goes – that the person with Tess’s body and Anna’s consciousness is really Anna, while the person with Anna’s body and Tess’s consciousness is really Tess – and indeed, this seems to most people to be the most natural description of what happens.
Or consider James Cameron’s film Avatar, released in 2009. Jake Sully, a disabled former Marine, ends up having his consciousness transferred into a different body, while on a mission in outer space to Pandora. Here there’s an added wrinkle: the body to which his consciousness is transferred is not even a human one. Rather, it’s Na’vi, a species native to Pandora. As in Freaky Friday, we’re meant to believe – and it seems natural to believe – that Sully goes where his consciousness goes. Though his human body dies, Sully – the very same person – survives in the Na’vi body that now houses his consciousness.
Though some philosophers have disputed that we should trust our intuitions in these kinds of cases (see especially Williams 1970), many philosophers take them to make a strong case that personal identity does not consist in sameness of body. But that’s not yet to say that Locke’s view has been established, for we might think that there is another possible view consistent with the body swap and consciousness transfer scenarios. Perhaps what’s important for personal identity is not sameness of consciousness, but sameness of immaterial substance, i.e., sameness of soul (see, e.g., Swinburne 1973–4 and Madell 1981). This kind of view about the nature of personal identity is often associated with dualist views about the nature of mind (see Robinson, Chapter 4, this volume). In the contemporary literature about personal identity, it is often referred to as the simple view.
In defending against the simple view, Locke asks us to consider a different kind of case. Consider Thersites, a figure from Greek mythology who was supposedly present at the siege of Troy. Now suppose that souls exist, and that someone existing today – call him Sunil – happens to have Thersites’ soul. Is that alone enough to make Sunil the same person as Thersites? Locke suggests that such a supposition would be absurd. For example, as depicted by Homer in the Iliad, Thersites was struck across the back and shoulders by Odysseus in response to his having sharply criticized Agamemnon; after being hit, he sat cowering, crying, and in pain. But presumably Sunil can’t extend his consciousness backward to that experience no matter how he tries. On Locke’s view, merely having the same soul as Thersites is as incidental to Sunil’s personal identity as if Sunil’s body happened to be made up of some of the same particles of matter that once constituted Thersites’ body. As he argues, “the same immaterial Substance, without the same consciousness, no more [makes] the same Person, by being united to any Body, than the same particle of matter, without consciousness united to any Body, makes the same Person” (Locke 1689/1975: 339–340).
As these considerations suggest, there is something eminently plausible about a theory that explains personal identity in terms of episodic memory. But that said, Locke’s own specification of the view is threatened by several counterexamples. Recall that Locke requires that for a presently existing individual to be the same person as some past existing individual, the present individual must be able to extend her consciousness backward to the experiences of that past individual. Since persons are prone to forgetting all sorts of experiences they’ve once had, this requirement runs into serious trouble. Writing in the late 18th century, Thomas Reid forcefully spelled out the problem with what’s become known as the Brave Officer case (Reid 1785). Consider a brave officer, who while on a military campaign, engages in a heroic act. As a young boy, this same man had stolen some apples from a neighbor’s orchard. And now, as a retired old man, he has become senile. Though he still remembers his military career, including his act of heroism, he no longer remembers stealing the apples. But assuming that while he was in the military he still could remember this childhood theft, we’re presented with a paradox. Since the retired old man can extend his consciousness backward to recall the experiences of the brave officer, they are the same person. Since the brave officer can extend his consciousness backward to the young thieving boy, they too are the same person. According to the principle of the transitivity of identity, if a is identical to b, and b is identical to c, then a is identical to c. So it seems to follow that the retired old man is identical to the young thieving boy. But since the retired old man cannot extend his consciousness backward to recall the experiences of the young thieving boy, Locke’s theory would deny that the retired old man is identical to the young thief. The theory thus seems to lead to a contradiction.
2 The Continuity of Consciousness View
In response to this kind of worry, philosophers sympathetic with the spirit of Locke’s view tend to suggest a modification of it. Rather than requiring that there be direct connections of memories between two individuals for them to count as the same person we can instead require simply that there be a continuity of memory between them. It doesn’t matter, then, that the retired old man can’t directly extend his consciousness backward to the experiences of the young thief. Since he can extend his consciousness backward to the experiences of the brave officer, who in turn can extend his consciousness backward to the experiences of the young boy, the experiences of all three stages are part of the same shared continuity of consciousness. Let’s call this the continuity of consciousness view.
While the continuity of consciousness view avoids the problem posed by the Brave Officer case, views in the Lockean spirit face another objection that cannot be dealt with so easily. The Brave Officer problem arises essentially due to cases of forgetting.2 But in addition to the fact that some of our memories can be forgotten, there is also the fact that some of our memories can be false. When I extend my consciousness backward to some event, I take that to be an event that I myself experienced. But what if I’m wrong?
Cases of mistaken memories are not at all uncommon. Consider this scenario: Jordan starts recounting a story about a time he beat up a bully who was taunting a group of younger kids. In fact, his brother Zach was the one who pummeled the bully. (“Hey, that wasn’t you, that was me!” he m...
