What can science prove?

[Frank]

You haven't demonstrated how it is knowledge at all. All you have demonstrated is that you think knowledge depends on the largest amount of data available...it doesn't. You have provided no proof, only reasoning based on an assumption of materialism and data collection. If materialism isn't true, your "proof" evaporates. If the data collection changes to support another theory, your "proof" evaporates.

The idea of a proof is that it cannot possibly evaporate under any circumstances. Otherwise it wouldn't be a proof...

I disagree. I'm simply saying a priori and posteriori knowledge doesn't require proof in the way you're demanding. The fact that tunafish exist is posteriori knowledge, and it is an allowable presumption we can base conclusions on. Deductive reasoning is not itself proof, but if the argument structure is sound (that is if each presumption used to reach its conclusion is based on sound empirical data, or can be properly defined as a priori or posteriori knowledge) then it's proper to couch it as a true conclusion (and one reached with the assistance of scientific knowledge).

In my tunafish example, I narrowed the argument to exclude any exceptions. I didn't make a statement about all tunafish that potentially exist throughout the universe, or all tunafish that may have existed in the past, I narrowed my reference to tunafish that are currently alive on earth. Indeed I even narrowed it further (I predicated the argument by saying 'assuming all the fundamental laws of nature remain unchanged').

A long time ago someone came up with the idea of combining iron ore with coke and other minerals (like manganese, nickel, chromium and vanadium) to make a stronger, harder, and lighter metal than the iron that was commonly used (which we today call steel). Up until they actually produced steel their formula was merely a theory (that had a certain probability, something less than 1, of working). Once they actually produced steel, they proved their idea was correct. They didn't almost prove how to make steel, they conclusively proved how to make steel.

If I say the moon (as it existed during the moon landing) was made partially of rock, what are the chances this statement could be wrong? I contend the chances are zero, because we collected samples when we visited the moon, and they were shown to be rock. Certainly you can say if I made the same statement regarding the state of the moon as it exists this instant, although the probability I'm right may be extremely high, it's not absolute (because we can't rely on the uniformity of nature). Nonetheless, I'm able to take data collected by science and make statements that are 100% true. Of course a properly structured tautology can be absolutely true as well (but I'll spare you the semantics).

It boils down to how we phrase it. Science can conclusively show some things are true, by validating theories through experiments. Take the example of steel. It is true if the fundamental laws of nature become altered - the formula for producing steel may no longer work. However, a conclusive statement is made by simply qualifying it (e.g. predicating it with a series of assumptions, like assuming the fundamental laws of nature remain unchanged). So when people point to the weaknesses of science (and indeed there are many weaknesses in science), we need to put it in perspective. IMO you're defining the concept of "conclusiveness" so broadly that it loses substantive value.

[LukeMC]

I disagree. I'm simply saying a priori and posteriori knowledge doesn't require proof in the way you're demanding. The fact that tunafish exist is posteriori knowledge, and it is an allowable presumption we can base conclusions on.

And that's all it is. A presumption. It cannot be proven and hence anything based off it cannot be conclusive. As allowable or reasonable as the assumptions may intuitively be, the fact remains that we cannot prove tunafish to exist. Everything beyond "I think therefore I am" could simply be a delusion of the mind. It doesn't matter what is sensible or intuitive. The possibility is real and therefore science can never prove anything to be concrete and absolute beyond any reasonable (or unreasonable) doubt. As Adrian said, refer yourself to the China thread. It's all ridiculous and tedious but valid insofar as it shows that we cannot prove things scientifically.

[Frank]

I disagree. I'm simply saying a priori and posteriori knowledge doesn't require proof in the way you're demanding. The fact that tunafish exist is posteriori knowledge, and it is an allowable presumption we can base conclusions on.

And that's all it is. A presumption. It cannot be proven and hence anything based off it cannot be conclusive. As allowable or reasonable as the assumptions may intuitively be, the fact remains that we cannot prove tunafish to exist. Everything beyond "I think therefore I am" could simply be a delusion of the mind. It doesn't matter what is sensible or intuitive. The possibility is real and therefore science can never prove anything to be concrete and absolute beyond any reasonable (or unreasonable) doubt. As Adrian said, refer yourself to the China thread. It's all ridiculous and tedious but valid insofar as it shows that we cannot prove things scientifically.

That's a philosophical opinion, and not fact. Here's another hypothetical. Assume I'm in the supermarket right now, and I'm staring at a tunafish for sale in the sea food section, and I'm responding to this on my iphone (I'm not really, but assume I am). I would be able to say, at this instant, I'm absolutely sure tunafish exist on earth. Why, because I'm looking at a tunafish.

You might say I can't conclusively say that because I can't even be sure I exist. But I am sure I exist, because a priori knowledge (that rests on a priori justification) can be conclusive. You may take a different view, but nonetheless my view is valid and mainstream (although I acknowledge there's a variety of opinions on this). Moreover, there are statements that are absolutely true in all possible cases (e.g. necessary propositions).

I understand it's popular to say science can't conclusively prove anything; but pay special attention to "why" some people say that. That notion is predicated on the assumption that we can't be sure whether or not we really exist, much less rely on the uniformity of nature. However, it's only a technically accurate statement if the stated conclusion is overly broad; and you reject the validity of a priori knowledge (at least insofar as the conclusiveness of our existence). Once again there's differing views on this.

If a scientist was holding a tunafish and you asked him how sure he is that it's a tunafish he's holding, most would answer absolutely sure. If you asked your long haired philosophy professor (who has bongs hanging from his office ceiling), he will almost certainly give you a different answer; and you better pack a lunch - because it will be a very long and belated answer.

***oh yeah, I should have said "assumption" (not "presumption") in the previous post ... apologies.

[LukeMC]

You might say I can't conclusively say that because I can't even be sure I exist. But I am sure I exist

Doesn't matter how sure you are. You have no proof beyond "reasonable", "allowable", "mainstream" assumptions. In the every day, colloquial sense of "proof", sure, everything you're saying is correct. But in it's strictest sense, no. It is in that strict, perhaps overly pedantic sense that my argument presides. You can prove things to a level of absolute certainty to people, yet still not have it proven as a certainty itself.

I'm with the philosophers on this one. I believe that's where the philosophy of science lies.

[Frank]

You might say I can't conclusively say that because I can't even be sure I exist. But I am sure I exist

Doesn't matter how sure you are. You have no proof beyond "reasonable", "allowable", "mainstream" assumptions. In the every day, colloquial sense of "proof", sure, everything you're saying is correct. But in it's strictest sense, no. It is in that strict, perhaps overly pedantic sense that my argument presides. You can prove things to a level of absolute certainty to people, yet still not have it proven as a certainty itself.

I'm with the philosophers on this one. I believe that's where the philosophy of science lies.

If some philosophers would like to think there's a transcendent definition of certainty that's fine by me (and I might not necessarily disagree, depending on context), but it still doesn't preclude what I'm trying to say. It's a matter of context. For instance, if I qualify a statement (by saying "assuming I exist and the laws of nature remain unchanged") then I can make conclusive statements.

[Tiberius]

In my tunafish example, I narrowed the argument to exclude any exceptions. I didn't make a statement about all tunafish that potentially exist throughout the universe, or all tunafish that may have existed in the past, I narrowed my reference to tunafish that are currently alive on earth. Indeed I even narrowed it further (I predicated the argument by saying 'assuming all the fundamental laws of nature remain unchanged').

You narrowed the argument yet there are exceptions. As I said before, you have not proved that tunafish exist (they may all be delusions we suffer). Nor have you proved that every single one will die, since you have no method to know where each tunafish on Earth is (one may be in the very centre of the Earth, protected for all time). Your assume these things are true, and base your conclusion off these assumptions. It isn't a proof. Proofs cannot possibly be wrong, otherwise they would not be proofs. Do you agree? If you do, then you should be able to see my line of reasoning clearly. There are always exceptions, always other hypothetical situations that are "possible", and thus science does not prove anything, but puts a probability on one of the hypothetical situations, saying the evidence matches it the best.

A long time ago someone came up with the idea of combining iron ore with coke and other minerals (like manganese, nickel, chromium and vanadium) to make a stronger, harder, and lighter metal than the iron that was commonly used (which we today call steel). Up until they actually produced steel their formula was merely a theory (that had a certain probability, something less than 1, of working). Once they actually produced steel, they proved their idea was correct. They didn't almost prove how to make steel, they conclusively proved how to make steel.

How do you know (conclusively) that this will always work; that the reasons we think this material is so much stronger are accurate? Your philosophy seems to be "try something, if it works, it must be correct". Do you think Newton proved how gravity works then? His model worked for years, and by your standards he "proved" how gravity worked, but then an anomaly came up, and Einstein came up with a new theory to explain gravity better. So Newton's "proof" wasn't a proof, and we cannot say conclusively that Einsteins is either. We don't know the future...we cannot predict the anomalies.

If I say the moon (as it existed during the moon landing) was made partially of rock, what are the chances this statement could be wrong? I contend the chances are zero, because we collected samples when we visited the moon, and they were shown to be rock. Certainly you can say if I made the same statement regarding the state of the moon as it exists this instant, although the probability I'm right may be extremely high, it's not absolute (because we can't rely on the uniformity of nature). Nonetheless, I'm able to take data collected by science and make statements that are 100% true. Of course a properly structured tautology can be absolutely true as well (but I'll spare you the semantics).

You claim your statements are 100% true, but there are still possibilities that might show them false:

1) The technology that showed the moon rocks was "rocks" gave errors...repeatedly.
2) The scientists made errors and wrongly pronounced the material as rock.
3) The moon is actually made of cheese, but when we landed on it, a supernatural being altered it to look like rock. The "rocks" we currently have are still disguised, but they are cheese nonetheless.

Are these possibilities absurd? Yes. Are they highly unlikely? Yes. Does that mean the theory about moon rocks is true? Hell no. Truth doesn't have possibilities. Truth has one value. Something is either true or not, and whilst there are multiple possibilities, one cannot say anything about the truth value, only which is the more likely possibility.

It boils down to how we phrase it. Science can conclusively show some things are true, by validating theories through experiments. Take the example of steel. It is true if the fundamental laws of nature become altered - the formula for producing steel may no longer work. However, a conclusive statement is made by simply qualifying it (e.g. predicating it with a series of assumptions, like assuming the fundamental laws of nature remain unchanged). So when people point to the weaknesses of science (and indeed there are many weaknesses in science), we need to put it in perspective. IMO you're defining the concept of "conclusiveness" so broadly that it loses substantive value.

I'm not the one defining conclusiveness broadly...you are the one defining "proof" too loosely. I have no doubts science makes conclusions, in fact I've argued this repeatedly. However, it is wrong to say these conclusions are anything other than the most probable answer. There is scientific truth, and there is absolute truth. Scientific truth is whatever science deems is the most probable explanation for the event. The absolute truth is the actual explanation for the event.

It might be that the scientific truth is the absolute truth in some situations, but this is not provable, nor is it a valid way to look at science. In fact, it's a very anti-science thing you are doing; saying science conclusively proves something. You are closing science to the very thing that makes it powerful...re-examination. If we hold Einstein's theories of gravity to be "proven", then we create a dogma around that theory, and any other data that seems to contradict Einstein is thrown out. Why? Because something that is "proven" cannot be contradicted...it is impossible by definition. Luckily, we do not hold that science proves anything, and with this we are able to move forward with more research.

[LukeMC]

For instance, if I qualify a statement (by saying "assuming I exist and the laws of nature remain unchanged") then I can make conclusive statements.

The fact that you must make those assumptions is what holds my argument together. Strictly speaking, we cannot know the second assumption to be true- we merely make the deduction that it is due to our past experience with it. That's not to say that things can't change tomorrow; we cannot rule out the possibility of supernatural occurences in the same way we cannot conclusively rule out the possibilty of a god. It COULD happen. As such, the extent to which science can claim "proof" is limited by this exceptionally thin margin of uncertainty.

[Tiberius]

To back Luke's point up:

An assumption is by definition something that is not necessarily true. If you rely on an assumption to make a conclusion, you cannot hold that conclusion as absolutely true, but true relative to the validity of the assumption.

Science relies on the assumption of materialism. Anything deduced or "concluded" by science is relying on materialism being true.

[theVOID]

Science can't 'prove' anything, but it is still easily the single best methodology for ascertaining the likelyhood of something being true or false.

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To back Luke's point up:

An assumption is by definition something that is not necessarily true. If you rely on an assumption to make a conclusion, you cannot hold that conclusion as absolutely true, but true relative to the validity of the assumption.

Science relies on the assumption of materialism. Anything deduced or "concluded" by science is relying on materialism being true.

That's not true, the manifestation of supernatural or non-material entities (should they exist) in reality would still be measurable, so it's false to say science operates on the assumption of materialism, it is simply the case that everything ever observed in (or acting upon) reality has a (most likely) materialistic origin. The simple fact that the best explanations for any phenomenon (in terms testability, repeatability, explanatory power and the ability to make predictions) are materialistic in origin does not mean the supernatural is discounted by default.

[Violet]

You narrowed the argument yet there are exceptions. As I said before, you have not proved that tunafish exist (they may all be delusions we suffer). Nor have you proved that every single one will die, since you have no method to know where each tunafish on Earth is (one may be in the very centre of the Earth, protected for all time). Your assume these things are true, and base your conclusion off these assumptions. It isn't a proof. Proofs cannot possibly be wrong, otherwise they would not be proofs. Do you agree? If you do, then you should be able to see my line of reasoning clearly. There are always exceptions, always other hypothetical situations that are "possible", and thus science does not prove anything, but puts a probability on one of the hypothetical situations, saying the evidence matches it the best.

But even delusions exist, Adrian. Their existence, while not tangible, remains a fact. If they did not exist, you could not consider them.

Of course, everything that we think is tangible could easily be an elaborate delusion. All things (tunafish included) exist as concepts, and we've no capacity to rationalize a things existence outside of its being a concept (as to do so we would have to make it a concept). We have no evidence that we do not generate our reality as concepts... and therefore the statement that nonexistence exists could be as equally valid as stating that anything else exists (all the more so when it exists outside of logic).

By this definition of proof (that it cannot possibly be wrong)... we have opened the door into questioning what is possible (As well as what is 'right' and 'wrong'). We have no grounds save anecdotal ones to consider that which exists outside of logic (which evidently things can) as being not possible. Therefore proof in the sense that we could know a thing cannot possibly be wrong is impossible (Or is it in fact? )... hence the question of "What can science prove?" (which is already based on the 'proof' being 'impossible') is a loaded question.

The fact that you must make those assumptions is what holds my argument together. Strictly speaking, we cannot know the second assumption to be true- we merely make the deduction that it is due to our past experience with it. That's not to say that things can't change tomorrow; we cannot rule out the possibility of supernatural occurences in the same way we cannot conclusively rule out the possibilty of a god. It COULD happen. As such, the extent to which science can claim "proof" is limited by this exceptionally thin margin of uncertainty.

There is only assumption when it comes to what we know... what else would our knowledge be based on? We could certainly know things to be true... but that doesn't mean we're 'right' in our knowledge.

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That's not true, the manifestation of supernatural or non-material entities (should they exist) in reality would still be measurable, so it's false to say science operates on the assumption of materialism, it is simply the case that everything ever observed in (or acting upon) reality has a (most likely) materialistic origin. The simple fact that the best explanations for any phenomenon (in terms testability, repeatability, explanatory power and the ability to make predictions) are materialistic in origin does not mean the supernatural is discounted by default.

Nor indeed should they be considered as supernatural or non-material... for they are simply another part of a 'greater' nature and of different substance that is immaterial (if indeed such things exist, which they like all other things do).