Can experience be used to predict the future?

charlatan said:
Also, for those who suggest that the fact something hasn't been falsified till now does not imply much confidence about the future, Popper is still addressing that. He's saying that, if our theory is highly falsifiable, we'd find that it can be destroyed quite easily. So, one might surmise, if it hasn't been destroyed yet, it's proven its use {BTW, in reference to some of Ren's discussions, here's when there's some sliver of pragmatism that creeps into a theory that's nonetheless aiming for truth, not just to be useful}.
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That bit was so interesting man, thanks for that :) I like how you managed to "reconcile" Popper's view with the pragmatist's utility-based approach that I tried to express - from an outsider's perspective - in one of my earlier posts.

@wolly.green Do you think this is consistent with Popper's arguments in Conjectures and Refutations?
 
Ren said:
That bit was so interesting man, thanks for that :) I like how you managed to "reconcile" Popper's view with the pragmatist's utility-based approach that I tried to express - from an outsider's perspective - in one of my earlier posts.

@wolly.green Do you think this is consistent with Popper's arguments in Conjectures and Refutations?
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Hi!

No not really. I believe Popper refuted pragmatism. In summary, his refutation goes something like this. Saying that the purpose of creating a theory is to make predictions is the same as saying that the purpose of driving a car is to burn fuel. Burning fuel is only one of the many things a car must do in order to achieve its goal. In the same way, making accurate predictions is only one of the many things that a theory must do in order to achieve its ultimate goal -- explain reality. There is no room for pragmatism in Popper epistemology.
 
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There seem to be various flavors of pragmatism.

I think the main point that would be contested by some of the modern pragmatists (who reject logical positivism about as thoroughly as Popper would) is whether we can falsify theories. The reason this is crucial is that Popper draws the distinction between knowing one's theory is wholly true and knowing it is false.... that we can know it's false is part of why he views what some frame as induction as actually deductive.
Now someone like Hume perhaps would ask: so what if we falsified a theory -- even if we know certain regularities do not always hold, perhaps they will in the future, and perhaps they won't. That we falsify a theory that they always hold doesn't do much, by this view, because the prediction is part of the theory, and the predictive range is also something we can vary. Since we can vary it as much as we like, perhaps radical skepticism beckons again. That is, if a theory suggesting certain predictions has held till some point in time, unfortunately we can't, it seems, tell between a variation that says they hold till that point and don't from then on out.... until we in fact discover it wasn't falsified.

I see pragmatists' views as a (not really satisfactory, because to me it retreats into a corner while dodging a lot of important question.... but nonetheless hard to not sympathize somewhat with) response to things like the above/ a retreat into the idea of theories as useful fictions for making predictions (where the predictions are not, at least by the more radical, given any superior reality value, being really part of the theories themselves).
Perhaps they'd say that, given we are realists, sure it's absurd to talk of limiting a theory's function to its predictive value. However, that realism is just what they might deny/some of the famous ones do deny.

Now I certainly never meant to mislead that Popper would directly endorse any version of this. However, he seems to have known about the idea that falsification might not be as obviously possible as one may think, and here he seems to basically suggest taking one's experiences seriously.

I need to revisit this part in detail, but my present understanding is that Popper suggests certain methodological conventions which will serve to promote the kind of falsification good science seems to in fact follow. I can't help but ask if saying we ought to work with certain methodological conventions that ensure we take our experiences seriously.. isn't somewhat resembling of the idea of "let's just go ahead and agree that our goal is to make predictions" and somewhat reducing the force that the predictions would actually falsify something rather than merely be initially stated goals. I mean, these aren't exactly the same, but the spirits seem to be getting at least a sliver similar.
 
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Just to betray my own sympathies, I'm still partial to the idea of good explanations over any kind of instrumentalism/theory of useful fictions to make predictions, mainly because it seems to me the most general framework one can work in and provides good answers to the standard instrumentalist concerns. I fail to see the merit in retreating to instrumentalism by radically questioning if a theory is describing a really real, truly real world, because really, even if no explanations are possible whatsoever, one is making a theory/explanation of some kind, and it's better to have a criterion of truth regardless of whether one is able to achieve it, and have that criterion be difficulty to vary one's explanation. If there is no truth, simply remain silent.

And quite honestly, this seems to address even some of the most radical antirealism/skepticism a pragmatist might put forth: maybe two people come up with distinct theories, and we can't decide between them, and we have no idea if the theories describe a genuine real world. But surely we can say our pursuit is still described as aiming to seek hard to vary explanations, and the problem of multiple theories that can't be decided among is just a statement that we haven't found an answer to the hard-to-vary part.
That seems a more general pursuit than that of making predictions, because it seems to me the point of predictions is to make explanations hard to vary, and assuming it's the only way to do so is hardly justifiable to me.
 
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charlatan said:
There seem to be various flavors of pragmatism.

I think the main point that would be contested by some of the modern pragmatists (who reject logical positivism about as thoroughly as Popper would) is whether we can falsify theories. The reason this is crucial is that Popper draws the distinction between knowing one's theory is wholly true and knowing it is false.... that we can know it's false is part of why he views what some frame as induction as actually deductive.
Now someone like Hume perhaps would ask: so what if we falsified a theory -- even if we know certain regularities do not always hold, perhaps they will in the future, and perhaps they won't. That we falsify a theory that they always hold doesn't do much, by this view, because the prediction is part of the theory, and the predictive range is also something we can vary. Since we can vary it as much as we like, perhaps radical skepticism beckons again. That is, if a theory suggesting certain predictions has held till some point in time, unfortunately we can't, it seems, tell between a variation that says they hold till that point and don't from then on out.... until we in fact discover it wasn't falsified.
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I'm really struggling to understand your point. What I think you're trying to say something like: "Karl Popper claims that science proceeds through trial and error. When a scientist 'sees' a regularity in nature that seems unusual, he will try to explain it by looking through his repertoire of theories. If after looking through all of the available theories he finds that there is no explanation, he will try to 'explain' it by inventing a new theory. Inventing a new theory often involves: conjecture, criticism, experiment and variation. In short, a scientist will often invent multiple different 'explanations' of the same regularity, then will try to rule them out (falsify them) by using criticism and experimental testing. The explanation that survives extensive criticism will become accepted as true. However, the problem here is that there are always an infinite number of theories that are consistent with the same regularity. Therefore, it is impossible to 'rule out' all possible explanations."

This is true, but hardly a problem. You may not be able to rule out -- or falsify -- all possible theories, but why should this matter? If you have multiple competing theories that cannot be ruled out using experimental testing, it's always possible invent new means of testing. In fact, this is often how science progresses. If your tests fail to distinguish between two competing theories, invent a new experiment that will.
 
I'd say part of the thing is I'm not conveying just my beliefs; a lot of the above was anticipating what some of the pragmatists might bring up. Also, as you'll see, I'm not actually claiming there's a real, substantive problem that isn't resolved, more just being careful about the issues in question.

In a nutshell though, the point as I interpret it is that falsification is no more "absolute" in terms of the certainty we can have about it than truth-seeking. That is, predictions based on a scientific hypothesis involve, at least in general (if not always), theoretical assumptions themselves -- thus, it's not like we can just logically deduce a falsehood from our hypotheses (and thus reject the hypotheses) at least in general.

Of course, this whole line of reasoning disappears if we basically build the predictions into our theory itself (agree on what makes sense as a test, what methodology to adopt, and so on). And this is exactly what Popper appears to suggest based on possible objections to his falsification idea, but he is cognizant that we need to actually work out conventions that ensure experience is taken seriously. However, this is where the spirit that we're playing a "prediction game" seems to creep in.

None of this poses a problem for someone who is comfortable with a not-so-strict line between science and philosophy/reason generally construed.
(So it doesn't pose a problem for me in particular.)

But you can see how some of this would lead some inclined to a kind of hardcore skepticism about the possibility of falsification (in particular some of the pragmatist/antirealist camp) to suggest that the theory-laden nature of prediction suggests that there's no naive way we can just falsify a theory based on observation. That is, our path from a hypothesis to a possible falsification is heavily influenced already by our theorizing, not just a matter of naive logical deduction.

I don't see a need to go to pragmatism about truth from any of this, because I don't see the need to have a strict, naive path from theory to observation in order to believe in truth-seeking. However, I can imagine someone going the "it's a prediction game based on our agreeing on the conventions" route.
 
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wolly.green said:
This thread is about induction. So is induction possible? Is it possible to derive scientific knowledge – or any knowledge for that matter – from inductive inferences? Sunrise is the famous example that is used to illustrate induction, so we will start with that. Don’t worry if you’re scratchy on the details, it will all make sense soon.

We have all experienced a sunrise. It’s that time of day when the sun ascends above the horizon and into the sky. Over the years, we have come to not only know what a sunrise is, but to actively expect it. Morning after morning, we all expect the sun will rise, even if we cannot see it beyond a cloudy sky. And surely enough, morning after morning our expectations are verified. But how did we come to know and expect that the sun will rise? Induction says that we “know” the sun will rise because we have extrapolated it from experience. Day after day, we have exactly the same experience of the sun ascending above the horizon, and thus extrapolate from those experiences that it will ascend again in the future. However, is this really how we come to “know”? Do we really gain knowledge about what to expect by extrapolating from experience? I want to argue that this cannot be the case. One problem to consider is: how do we ever know when two experiences are the same?

How do I know when two experiences are identical? I may have experienced a sunrise today, but how do I know that I have experienced a sunrise in the past? I may label these two experiences with the same name – I may call them both ‘a sunrise’ – but how do I know they are the same? One answer is: I can say two experiences are identical if I experience them under the same conditions. For example, I know that one condition for a ‘sunrise’ is that it must happen in the morning. I know another is that it cannot without a sun. But this leads to a further question: how do you know which conditions are related to which experience? The answer, I think, is because our explanations tell us so. The fact that a particular experience is related to some set of conditions is itself a conjecture; a creative leap of imagination. But if we come to know two things are related though conjecture, then our prediction that the sun will rise in the future has nothing to do with extrapolation. Which implies that knowledge cannot be derived through induction.

What about a law? There could be a law of induction that tells us when two experiences are identical. If we had such a law, we could use it to make inductive inferences because it answers our question: how do we know two experiences are the same? However, the problem with this approach is that no one has yet discovered such a law. No one has yet to formulate one that is useful for deriving knowledge from experience. Therefore, until it has been discovered, it cannot be used to ‘justify’ induction.

In short, experience cannot be used to make predictions about the future. Nor can it be used to derive knowledge about anything. Thoughts?
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This ties in with the black swan theory
 
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