4. The “resolve and follow through” strategy

Can teleportation be verified by trying the machine out for oneself? The skeptic says no, claiming that, should the person who originally entered the machine—you, in our dramatization above—awaken on Mars, he would not be able to tell whether he was real or copy, and thus whether the machine had worked or failed. Should this claim be true, I’d concede the matter at once, so everything hinges on whether the skeptic can establish this claim.

As we saw, the skeptic’s reason for it seems simple enough at first. What it’s like for the original subject to wake up on Mars is exactly like what it’s like for the copy to do so. So the person who wakes up on Mars, whether original or copy, wouldn’t be able to tell who he was, and thus whether the machine had worked or failed. In particular, the original subject, should he awaken on Mars, wouldn’t be able to tell.

I pointed out that there must be more to the reasoning than this, because of the fact previously noted, viz., that the original subject, rousing on Mars, could never judge wrongly that the machine had worked.—Should he awaken on Mars, go by his memory, and judge that the machine had worked, his judgment would be bound to be correct. Consider, as such, that the original subject, knowing as much, could simply resolve (at the outset) to go by his memory and judge that the machine had worked should he seem, upon pressing the button, to find himself waking up on Mars. It should be plain that this strategy could never fail him, i.e., that, following this strategy, he could never end up judging that the machine had worked, when it actually had failed. The strategy could only ever fail the copy, should he wake up on Mars; that is to say, should the copy awaken on Mars and “follow through” on the resolve in question, he’d end up judging wrongly that the machine had worked. But this may not be an issue, since, depending on the case, the original may not care if the copy should judge wrongly that the machine had worked; indeed, the copy himself may not care. To see what I mean, consider the following case.

Suppose that the original subject is the sort of person who would consider a copy’s life to be worthless, nothing short of a sham—the way a molecular duplicate of the Mona Lisa might be deemed worthless, say, when compared with the original. The copy, should he materialize, would then inherit this attitude. Under these circumstances, the person who wakes up on Mars, original or copy, may be expected to follow through on the original subject’s resolve to go by his memory and judge that the machine had worked. Regardless of whether he was original or copy, that is, we may expect him to judge that the machine had worked, following the original resolve to do so. We may think of this in something like the following terms: he’d wake up on Mars, seem to remember having entered the machine, and—“recalling” his earlier resolve to just go by his memory—sally forth to judge that the machine must have worked. Since his “memory” of having entered the machine would be fully compelling, there would be no particular psychological difficulty in thus bringing himself to judge, or otherwise accept, that the machine had worked. He’d simply trust his memory, as we’d normally say. In doing so, to be clear, he’d risk judging wrongly that the machine had worked, should he be the copy (thereby sounding his death knell, since he’d be bound to use the machine again, having judged that it works), in exchange for the potential reward of judging correctly that the machine had worked, should he be the original subject. But he may reckon this an excellent bargain, since a copy’s life is anyway worthless, whereas having the original subject judge correctly that the machine had worked was the point of it all.

So, in a case like this, as mentioned, we may expect this person, original or copy, to go by his memory and follow through on the original subject’s resolve to judge that the machine had worked. And the point that I wish to make now is that, should he happen in fact to be the original subject, then it seems to me, not merely that he’d thereby have judged correctly that the machine had worked, but that he’d know that the machine had worked. For his correct judgement that the machine had worked would have been arrived at here via a principled strategy—the “resolve and follow through” strategy just described—and can in no sense be deemed a fluke. It cannot be said, for instance, that he was just lucky that the machine happened to work, and that his judgement could quite easily have been wrong. If the machine hadn’t worked, it would not have been his judgement that would have been wrong, but someone else’s – the copy’s. And so I submit that, in such circumstances as those just described, the original subject, should he rouse on Mars, would know that the machine had worked.
If so, then the fact that waking up on Mars as the original subject is exactly like waking up on Mars as the copy, does not automatically entail that the original subject will be unable to tell who he was, or whether the machine had worked, should he awaken on Mars. For should the original subject succeed in executing the “resolve and follow through” strategy just mentioned, he’d know that the machine had worked, in spite of the mentioned fact.

The contrast with the brain defect case may again make this plain. The talk here is in terms of genuine versus false memory, but the point is the same. In the brain defect case, there is only one subject, so the fact that having the genuine memory is exactly like having the false memory is a fact about his memory alone, and does mean that he will be unable to tell if he has the genuine memory or the false one. (If he goes by his memory, he could well get it wrong.) In our case, there are two subjects, one with the genuine memory, the other with the false one, and this makes a difference. The subject with the genuine memory need not be concerned about having a false memory, since there is no possibility of this happening. (If he goes by his memory, he could never get it wrong.) This matters, for our purposes, since our concern is only with whether the subject with the genuine memory—the original subject—may safely go by his memory. The answer seems to me to be yes, and, moreover, that if nothing prevents him from doing so, he will come to know what his memory tells him.

It seems to me, therefore, that, to sustain his claim that the original subject would be unable to tell, or otherwise would not know, upon waking whether the machine had worked or failed, it’s not enough for the skeptic to reason that waking up on Mars as the original subject is exactly like waking up on Mars as the copy. His reasoning must also (somehow) contain the resources to show that the original subject would be unable to execute the “resolve and follow through” strategy proposed above, should it occur to him to do so; in particular, that the original subject would be unable to follow through on his resolve to trust his memory and judge that the machine had worked, should he wake up on Mars.

Given what has been said, it should be clear that this resource will be found within the skeptic’s reasoning if he presupposes, at some stage or other of his reasoning, that, far from being blasé, or otherwise unconcerned, about the possibility that the machine had failed—as in the scenario above where the copy’s life is deemed worthless—the person who wakes up on Mars would in fact want to know whether the machine had worked or failed, either way. That is to say, if he was the original, he’d want to know that the machine had worked, but, equally, if he was the copy, he’d want to know that the machine had failed.

This presupposition, if true, would block the original subject from following through on his resolve to judge that the machine had worked in the manner imagined above. For the thought that he might be the copy would now give him pause, since the copy, ex hypothesi, wouldn’t now want to get the judgement in question wrong any more than the original subject would. More generally, the effect of the presupposition would be to render the person who wakes up on Mars—whoever this may be, original or copy—conflicted over his identity, and to saddle him with a split personality à la Dennett’s protagonist above, vacillating between the personas of original subject and copy, the former inclining to believe that he was the one who originally entered the machine, the latter otherwise. Each persona would oppose the other, rendering the person who wakes up on Mars unable to follow through on his “remembered” resolve to go by his memory and judge that he was the original subject. He’d be rendered mute on the question of his identity, like the proverbial ass between two bales of hay.

This presupposition—that the person who wakes up on Mars would not be blasé or unconcerned about the possibility that the machine had failed—is actually quite natural and appropriate in many contexts, such as in Dennett’s story above. As mentioned, it’s essentially the same as saying that the copy, should he awaken on Mars, would want to know that the machine had failed, in the same way that the original subject, should he awaken on Mars, would want to know that the machine had worked. It would not be contrived at all for someone to presuppose such a thing in considering this entire issue. So it would not be untoward for the skeptic to do so either. All the same, it should be clear that the presupposition is not obligatory, and was not essentially built into our story. That the original subject would be concerned about whether the machine had worked or failed was so given: in particular, should the machine work, he’d want to know that it was really he who was waking up on Mars, and thereby that the machine had worked, since he was trying to see if teleportation could be verified in the first-person. But that the copy, should he awaken on Mars, would likewise be interested in knowing that he was, in fact, the copy, and thereby that the machine had failed, while consistent with our story, is not actually essential to it. In other words, the presupposition is not necessarily true, and in a case where it isn’t, as in the one imagined previously, the door is open for the original subject to execute the “resolve and follow through” strategy and thereby come to know that the machine had worked, should he wake up on Mars. This will be my essential contention in this essay. The case considered above where the original subject believes that a copy’s life is worthless is just one such case. The original subject might alternatively simply find the thought of being a copy ghastly, and would rather labour under the misapprehension that he was real than face the reality of being a copy. In this case too, the person waking up on Mars, a fortiori the original subject, may be expected to trust his memory and follow through on the original resolve to judge that he was the original subject. There are doubtless other cases. But I’ll stick to the first case throughout for simplicity, since I only need one. What is common to them is that the copy, should he awaken on Mars, wouldn’t care to know that the machine had failed.

And so the skeptic really does need the presupposition—the presupposition “that the copy would care,” as I will put it for short—in order to block the “resolve and follow through” strategy just discussed. We should expect this presupposition, therefore, to be nestled somewhere within the skeptic’s argument for his conclusion that the original subject would be unable to tell upon waking on Mars whether the machine had worked or failed. The skeptic’s main aim is to establish this conclusion, but his reasoning should “contain the resources,” as I put it above, to block the “resolve and follow through” strategy in passing.

Let me now suggest that the presupposition in fact figures in the skeptic’s reasoning in the most direct way possible, viz., as a supporting premise towards the conclusion just mentioned—i.e., in concert with the fact that waking up on Mars as the original subject is exactly like waking up on Mars as the copy. The existence of the “resolve and follow through” strategy was what raised the suspicion that this latter fact may not be strong enough to yield the skeptic’s conclusion, but we can also demonstrate this directly. In what follows, I will show that the skeptic can establish his conclusion—while blocking the “resolve and follow through” strategy on the side—only if he supplements the latter fact with the presupposition that the copy would care.