Friday, September 22, 2006

Why Believe in the Past?

The universe could have come into existence just now, false memories and all. What basis do we have for ruling out this possibility, or even thinking it unlikely? It's a bit ad hoc, I guess. It seems that positing a real history provides us with a better explanation for why things are as they are now. But this apparent benefit may be illusory. After all, we have no further explanation of why the universe ever began at all. Many atheists simply take it as a brute fact. But if we are tolerant of such bruteness, then why wait? It seems arbitrary. Worse, it's less parsimonious than doing away with the past altogether would be.

In short: if you're willing to posit the existence of the entire (4-d) universe as a brute inexplicable fact, why bother with the past at all? Why not cut to the chase and simply posit the brute existence of the present timeslice (and nothing else)?


  1. In physics there is even an argument which can be made for the hypothesis that all our memories of the past are deceitful. (Of course, it is not an argument that any physicist takes seriously). The idea is that entropy increases in time, and that higher entropy states have greater statistical probability. So the problem of explaining how a very low-entropy universe (like the Big Bang must have been) came to may be thought to be much larger to explain than the problem for a higher-entropy universe as the present state. If the universe arose from a random fluctuation, then a fluctuation producing directly the present with all its false memories is more "cheap" (less unlikely) that one producing a lower entropy state that can evolve into the present one. Sean Carroll explains the matter here.

  2. That should have been "came to be may be thought to be much larger"

  3. what would it mean for the universe to have "jsut come into existance"?
    In a sense I might argue it DID regardless of whether a previous time period exists or not of curse that would be a unusual definition - but this is an unusual thought experiment.

  4. My reason for believing that the universe did not come into existence just now is that I remember it being in existence yesterday.

    You might claim that this is a bad reason, because it is possible for the universe to have come into existence just now with a lot of false memories in place. I'll grant that it is possible for that to have happened. But so what? Pointing out a mere metaphysical possibility proves very little about my actual epistemic state. Unless you have some reason to offer for treating my memories as globally deceptive, or even profoundly unreliable, you have not yet given me any reason for doubting the evidence of my memory. But without some such reason, you've given me no reason to entertain your "might have been" as a "maybe" worth considering.

    Cf. Outwitting Old Nick for fuller remarks on the older version of the same puzzle.

  5. Yeah, I don't mean to be offering this as an aggressive argument for radical skepticism. Undermining existing beliefs is not the point. Rather, I raise the question from a neutral position. Suppose you came across a fence-sitter, who was uncommitted to the veridicality of their memories, and willing to take my scenario seriously as an epistemic possibility. My question is: on what grounds should they be led to posit past existence? Or could they just as reasonably believe the instant-universe scenario?

  6. Richard,

    Presumably, you don't just mean that the past still exists, but the observer is mistaken about it. Rather, you mean that the past is some sort of illusion.

    However, the past is just what we call the apparent time ordering of events. So it manifestly does exist by definition. No experience differentiates the two scenarios you are contrasting. So, why shouldn't we conclude that the question is meaningless because we don't know what it means for there to be no past when its experientially identical to having one?

    In other words, you've strung together a proposition (or a question) motivated by analogies and grammar. On what grounds should we be satisfied that we know the meaning of the question? Just by intuition?

  7. So skip those trivial problems of historical referential opacity and slaughter us with doubts about the existence of the past alltogether?
    The discussion/issue/problem disintegrates in your face as you repond to your other bloggers who posted ahead of you --that would be in the past.
    This is piss poor philosophy people.

  8. Well, for the record, I think it's neither piss poor philosophy nor true. Rather, the point of raising the "no past" hypothetical is to shed light on the question of what makes a good explanation, or a reasonable theoretical posit. If "anonymous" can't see the philosophical value in this, then the intellectual paucity is theirs.

  9. I am no good at writing. But I have often thought about time, present and history. I often thought about those people with short term memory. You know how certain people always live in the present, and forget everything about their past? For them, every minute is new and that just makes me wonder, if the past is just a creation of the brain, which we call memory, does it really mean there is a past? or maybe thats how far we can ever go, with this limited perception of ours. But maybe this is not a proper answer, since it is not an explanation rather asking more questions. But I only stumbled on your blog two days ago and though it is slightly difficult to understand, I thoroughly enjoy contemplating on these things and have been.


  10. I think that the simple justification is that IF time does not exist, then neither does reasoning or action because those are all processes which require time as part of their definition. That is, if time does not exist, then we are not really arguing that time exist, but instead we're trapped in a moment where we falsely perceive ourselves to be arguing that. So "we might as well" act as if time does exist, because we don't have anything to lose otherwise, although maintaining a vague doubt about time is probably better if we want to be truly rigorous. This is a lame sort of justification in my opinion, but I don't see what the alternative would be.

    (I'm new to blogs so I don't know what the proper etiquette is for posting in really old discussions, but if I'm making a faux pas at least aa made the same faux pas three days ago.)

  11. That's an interesting suggestion! I'm certainly receptive to such practical/"might as well" arguments, and I'm happy to have this as another example of one. Still, I feel that there also ought to be more traditional epistemic reasons we could appeal to...?

    (P.S. I welcome new contributions to revitalize old discussions. Thanks!)


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