Once upon a time – or outside of it, if we’re to have it Boethius’ way – having nothing else to do, God decided to conjure in His mind all the worlds He could bring into being were He so inclined. (By a ‘world’, at least at this planning stage, is meant that set of propositions that would be true of a world if God decided to make it.) Then having made a print-out of each, He began picking them up pairwise, keeping the one He preferred and consigning the other to the trash.
In virtue of what He preferred this one over that one shall forever remain a mystery to us. But that plays no part in this story. All that matters is that at the end of the day He held in His hand the one He most preferred. And then, still having nothing else to do, He brought it into being.
How He brought it into being shall forever remain a mystery to us. But that too plays no part in this story.
That’s Leibniz’ story and he’s stickin’ to it. And as the setup to my story, so am I. So here’s my story.
Sometime later – though how much later is what this is all about – someone came along and, having nothing else to do, decided to conjure up all the possible histories of this world that God had created. In other words, all the possible sets of the sets of propositions that could be true of this world, from the moment of its creation to and including the present moment. Then, having made a print-out of each, he began picking them up pairwise, trying to decide which was more likely to actually be the history of the world, his hope being that, at the end of the day, what he’d hold in his hand would be the print-out of the set of propositions most likely to be the true history of the world.
Why anyone would want to know the true history of the world shall forever remain a mystery to me. But that plays no part in my story. All that matters is that there are people who do. And that it’s my job, as a cheque-casher of the widow’s mite, to help them get what they want.
Some of these possible histories were fifteen billion years long, others a scant six thousand, and still others only five minutes. But unlike how God did it, how long ago He did it – or if He didn’t do it someone or something did – seems to be the one part of the story the taxpayer wants to see resolved. So let’s see if we can fill that in.
Now some people think that histories leave footprints. That’s how I can tell there was a prowler in the yard last night. But what makes me think that’s how I can tell? Don’t I have to already believe that footprints – which there clearly are! – are caused by the temporally prior footfall of feet? And how did I come to know that?
Well, presumably because I saw someone step on a patch of ground, and immediately thereafter there was a footprint that hadn’t been there before. One such observation doth not a causal relation make, but enough of them, in the right order and without exception, doth. That’s just what and all a causal relation is. Histories leave footprints because what it is ‘to leave’ is just another way of saying ‘to cause’. Whatever happened, whenever it happened, caused other things to happen. And so even if we can’t always trace backwards from what’s happening now to what must have happened sometime back then, we can be reasonably confident that there was something that happened back then which was among the causal antecedents of what’s happening now.
Well, perhaps. But doesn’t this presuppose that this footfall followed by this footprint was a single event? Isn’t it possible that the footprint was one event, and a second event was the memory of a footfalling? In fact isn’t that a more precise account of what actually transpired? So it’s not that you saw a footfall causing a footprint. Nor is it even, as David Hume suggests instead, that you inferred the causal connection between the footprint and the footfall. It’s that you inferred the causal connection between the footprint and the memory of the footfall.
But it seems to me that once one grants this, she’s given away the farm. For what comes next is the possibility that that memory is in fact a pseudo-memory. What if the world came into being just at the moment you observed the footprint, but it came into being with the pseudo-memory of a footfall in your head? How can this possibility be discharged?
Note that you can’t discharge it by citing your observation that this kind of thing just doesn’t happen, since that presupposes what needs to be shown. But there’s no way it can be shown.
So what is shown? That philosophers of science are wrong to argue that what disqualifies the Five Minute Hypothesis is that it’s non-falsifiable. It is non-falsifiable, but then so are any of the more standard hypotheses about the age of the world. What would count as evidence that whatever data we could appeal to to falsify some hypothesis could not be merely pseudo-remembered? Certainly not that we have data we can appeal to to falsify the hypothesis that that data is only pseudo-remembered.
These same philosophers of science insist that the asymmetry they need to dismiss if not discharge the Five Minute Hypothesis is that science is grounded on induction, induction on observation, and observation presupposes realism about the past. So the Five Minute Hypothesis cannot but be a species of scientific skepticism.
The argument is valid but unsound. Induction is not grounded on observation. It’s grounded on reports of observation. If the Five Minute Hypothesis is true, then what accounts for the fingers-crossed reliability of those reports is precisely what would account for their fingers-crossed reliability if the Five Minute Hypothesis were false. That is, if the Five Minute Hypothesis is true, we’ve just been damn lucky. But given that there’s no reason to suppose the future will resemble the past, if the Five Minute Hypothesis is false we’ve been just as lucky.
So contrary to its critics, the Five Minute Hypothesis is not a species of skepticism. Skepticism is not the view that we can’t know what’s true. It’s the view that we can’t rely on what we take to be true. Subscribers to the Five Minute Hypothesis put precisely as much reliance on those pseudo-history books and those pseudo-memories as does the straightforward realist about the past. And for the same reason. We’re all just crossing our fingers.
So why bother advancing the Five Minute Hypothesis if it makes no difference? Because it does make a difference. Not to science, but to ethics. It allows us to correct a number of metonymy errors in our ethical and political judgments. Such as? Well, it tells us that what’s wrong with pedophilia can’t have anything to do with the disparate ages of the participants. It tells us that entitlement can only be contingently a function of contribution. These are hard cases to make, but they’re made considerably easier when one can ask, “What if the world came into being only five minutes ago?” The most incorrigible intuitions immediately take a nosedive. Trust me. I’ve seen it.
In short, my colleagues are right. In flogging the Five Minute Hypothesis as I do, I am mad. But there is method to my madness.