Do you believe in Aliens? (Page 204)

AchillesSinatra: Or for banging gongs?

zeffur:

zeffur: "AchillesSinatra: I hesitate to return to Darwinian theory, but what do you think T-Rex's puny forelimbs were good for?"

Boogers, obviously. sheesh...

AchillesSinatra: More on Newton's laws (Newtonian mechanics) . . .


Among other exciting topics recently broached in the thread, the question of the truth/falsity of Newtonian mechanics has loomed large.

I've been arguing that Newtonian mechanics (i.e., Newton's laws of motion and gravitation) is false, even though--as all participants agree--it still yields predictions which are approximately correct (i.e., close to the true value) for most of our mundane, humanly experiences, i.e., when not careering around at close to the speed of light, or not enjoying an exotic vacation next to a black hole.

Lumpenproletariat and Zeffur have been arguing to the contrary, perhaps out of an admirable though misguided reverance for the great man, that Newtonian mechanics is not false. E.g.


"No it [Newton's theory of gravity] is not false. If it were, you would put in the same category as the geocentric theory, which you do not." - Lumpenproletariat (page 201)

"I disagree. It [Newtonian mechanics] was & still is true under certain conditions. It can't be considered true/accurate under all conditions as a universal truth would be--but it isn't necessarily untrue under all conditions." - Zeffur (page 200)





One of the books I happen to be reading right now is David Bohm's "The Special Theory of Relativity". For those not familiar with Bohm, the back cover has this to say:

"David Bohm (1917 - 1992). A close colleague of Einstein's at Princeton University after World War II, Bohm would himself go on to become one of the great physicists of the twentieth century . . . "


On page 87 we find this very clear passage (emphasis in original):

"It is clear that the form of Newton's laws of motion is NOT invariant under a Lorentz transformation. And since the experimental facts that have been discussed (as well as others) make it evident that the actual transformation between coordinate frames must be that of Lorentz and not that of Galileo, as well as that the laws of mechanics are indeed invariant to a change of velocity of the reference frame, it follows that Newton's laws CANNOT be the correct laws of mechanics (except as an approximation holding in the limiting case as v/c approaches zero)."



In other words (my words -- see above), Bohm is telling us:

"Newtonian mechanics is false, even though it still yields predictions which are approximately correct (i.e., close to the true value) for most of our mundane, humanly experiences, i.e., when not careering around at close to the speed of light, or not enjoying an exotic vacation next to a black hole."

zeffur: The following statements are for all intents & purposes approximately equivalent--I'm not disagreeing that Newton mechanics aren't 100% true--as a purist would be anal about--my point is that it doesn't matter much from a practical perspective & it is true (or true enough). Your nitpicking about an absolute true or false statement is rather unimportant, imo, because the difference is so negligilble (except near the light speed). Further more, when Quantum Gravity replaces Einstein Gravity & increases the accuracy even more, shall we call Einstein Gravity false? Yeah, of course, but will it make a huge practical difference anytime soon--or ever?? Not really--& probably not during our lives.

"I disagree. It [Newtonian mechanics] was & still is true under certain conditions. It can't be considered true/accurate under all conditions as a universal truth would be--but it isn't necessarily untrue under all conditions." - Zeffur (page 200)

"Newtonian mechanics is false, even though it still yields predictions which are approximately correct (i.e., close to the true value) for most of our mundane, humanly experiences, i.e., when not careering around at close to the speed of light, or not enjoying an exotic vacation next to a black hole." AchillesSinatra <somewhere in a chat forum, lol>

Lumpenproletariat: Achilles: "But -- going along with the gag, this means that the FLAT EARTH theory states as many true predictions as the SPHERICAL EARTH theory, so there is no way to test them to determine which is more correct." - Lump

I didn't say that. Strawman #1



"And you're claiming all the predictions of both are equally true or false." - Lump

I didn't say that. Strawman #2



So you think the astronauts passing over saw a flat earth just as well as a spherical earth, because all the observations confirm either theory equally the same, or refute either theory equally the same. - Lump

I didn't say that. Strawman #3.



OK, if you did not say that, then you're agreeing with me that:

For any alternative scientific theories, we know which is correct -- e.g. flat-earth vs. round-earth theory -- based on the predictions which either theory makes, and the one which ends up vindicated by testing/experience reality-check is the one which is correct, or is telling the truth.

In other words, some practical experiment is done to check which one made the correct prediction, and that one is the true theory (or more true than the other), while the one whose prediction turns out false is not the true theory.

And you agree that this is how we know which theory is true and which one is false, when 2 differing theories conflict with each other. This is how we know the earth is round and not flat. Or how we know that any theory is true or false.

And so if Einstein's theory is better than Newton's, it has to be because it made predictions which came true, when tested, while the Newton theory made contradictory predictions which turned out to be false, when tested.

And you're agreeing with this, because you agree that we can use the experience of the astronauts (e.g. what they saw from their capsule), and other common tests, as evidence that the earth is round rather than flat.

This is a common sense and correct explanation of how we know scientifically which theory is true and which one false, or which one is better than the other, when 2 theories contradict each other. They make some contradictory predictions about what happens if they're tested, and the one having the correct prediction, vindicated in the testing, is the correct or better theory.

I thought you disagreed with this, but you do agree with it.

And this principle applies to Creation vs. Evolution, where one is based on a claim that animals pop into existence suddenly, whereas the other says that all animals were spawned by earlier parents. And there is much more evidence, in experience, to show examples of the latter than the former.

Lumpenproletariat: Corwin: "The dinosaurs didn't go extinct. They built giant interstellar spacecraft and left. The climate was getting too chilly for their liking."




Not THE dinosaurs. There were quite a few of them, like a few million or billion (or trillion). Why should we assume that absolutely ALL of them were wiped out at one time? Many life forms did survive. Why assume that ALL the ones of that kind had to be wiped out?

Probably most mammals also were killed. But some survived.

The dinosaurs which survived were smaller ones, probably walking on 2 feet, which were in caves when the cataclysm took place They evolved over more millions of years. Why couldn't some of them evolve enough, in 50 million years, to become as intelligent as humans are today? and so develop higher achievements in science/technology?

This best explains any alien life (non-human intelligent life) which might exist and might have been encountered or observed, such as UFO sightings etc.

Lumpenproletariat: Achilles: "You've been arguing that Newtonian mechanics is not false, it's just been kinda improved upon. E.g.

"No it's not false." - Lump (page 201, and many similar remarks)"



It's not totally false. Because many of its predictions turn out true, maybe most of them. These true predictions can make it a mostly true theory.

But if it is superseded by a better theory (Einstein), it's because it's wrong on a few predictions where the Einstein is theory is right, when subjected to the same tests.

So it's the improved performance in the testing which makes the better theory correct in comparison to the earlier theory which is less true.

But that doesn't make the earlier theory entirely false. If it is still used for practical purposes, then it is still substantially true, even if it's not the best theory.

_____________

"Meanwhile Einstein speaks of the "Fictitious character of the foundations of his [Newton's] system". (also page 201)

How do you reconcile "the fictitious character of Newtonian mechanics" with your own "It's not false"?"



It's a largely true theory if it is used for practical purposes to yield true results, in testing.

But something true can still have false elements in it, so that a better theory could replace it.

If it was 100% false, then ALL its predictions would fail the tests and it would have no practical application whatever.

I'm sure there were earlier theories which were inferior to Newton's physics, making him an improvement on them, or more correct.

E.g., didn't Aristotle pronounce that all falling objects (in a vacuum) fall at different speeds depending on their weight? That has been replaced by a better theory (Newton? Galileo?) which tested this and found that they fall at the same speed if there's no air resistance.

So an earlier theory can be replaced by a later theory which is better, and yet even the later one can also be replaced. So the theories get better (and more true) as they get better and better at making true predictions which are tested. The replaced theory is not totally false just because it contains a fictitious element and is replaced by a better theory.

Even Aristotle's "false" theory was partly true.

AchillesSinatra: "OK, if you did not say that, then you're agreeing with me that:

For any alternative scientific theories, we know which is correct -- e.g. flat-earth vs. round-earth theory -- based on the predictions which either theory makes, and the one which ends up vindicated by testing/experience reality-check is the one which is correct, or is telling the truth."

- Lump



Do I agree? Of course, I don't.

First of all, "The Earth is Flat" and "The Earth is Round" are hardly what would normally be described as scientific theories. Both claims are simple, singular statements, as opposed to scientific theories which typically have a lot more "meat" to them, and tend to be general/universal in scope. Moreover, both claims go back to antiquity, and the matter was effectively settled by the ancients Greeks, long before anything we might call experimental science appeared on the scene.

As for for your claim that when two scientific theories are at loggerheads, it is in virtue of the predictions derived thereof that we know which "is correct, or is telling the truth", this is more nonsense, I'm afraid. To claim as much is to fall victim of the well known logical fallacy of "affirming the consequent", viz.

Premise 1: If my theory is true, then [such-and-such] will be observed

Premise2: [Such-and-such] is observed

Conclusion: My theory is true


The inference is, of course, fallacious -- the conclusion is not entailed by the premises. Any scientist worth his sodium chloride knows this, dude.






"In other words, some practical experiment is done to check which one made the correct prediction, and that one is the true theory (or more true than the other), while the one whose prediction turns out false is not the true theory.
And you agree that this is how we know which theory is true and which one is false, when 2 differing theories conflict with each other. This is how we know the earth is round and not flat. Or how we know that any theory is true or false." - Lump


This is the myth of the "experimentum crucis", or crucial experiment. It goes something like this:

1. Two (or more) rival theories are vying for our attention
2. A crucial experiment is performed.
3. Theory A is shown to be true, or at least confirmed; Theory B is shown to be false.
4. All scientists immediately and en masse recognize this, endorse Theory A and renounce Theory B.

This kind of thing never happens -- the kind of fairy-tale crap we often see in elementary science textbooks notwithstanding. No matter what the outcome of an experiment, there will always be scientists who continue to defend Theory B.

More to the point, why can there never be a crucial experiment of the kind you suggest? Ans: Because scientific theories of a general nature can neither be demonstrated (in the logical sense) to be true nor false. A theory which appears to sit uncomfortably with certain observations can always be defended by making adjustments to the concomitant "auxiliary hypotheses", or what we might simply call "background knowledge".

(See my thread on falsifiability for much more)





"This is a common sense and correct explanation of how we know scientifically which theory is true and which one false" - Lump

Common sense or not, it's quite wrong. See above.

Lumpenproletariat: Achilles: "On page 87 [Bohm] we find this very clear passage (emphasis in original):

"It is clear that the form of Newton's laws of motion is NOT invariant under a Lorentz transformation. And since the experimental facts that have been discussed (as well as others) make it evident that the actual transformation between coordinate frames must be that of Lorentz and not that of Galileo, as well as that the laws of mechanics are indeed invariant to a change of velocity of the reference frame, it follows that Newton's laws CANNOT be the correct laws of mechanics (except as an approximation holding in the limiting case as v/c approaches zero)."



In other words (my words -- see above), Bohm is telling us:

"Newtonian mechanics is false, even though . . ."


No, he's saying Newton's is less true than another theory which makes better predictions and therefore is more accurate than Newton's.


________________

". . . false, even though it still yields predictions which are approximately correct (i.e., close to the true value) for most of our mundane, humanly experiences, i.e., when not careering around at close to the speed of light, or not enjoying an exotic vacation next to a black hole."

He's saying It's less true because its predictions are less reliable when tested.

He's not simplistically saying "Newton's mechanics is false."

And what makes it less true is the less reliability of its predictions compared to the better theory. So it's not correct that all theories yield the same predictions, or an equal number of true and false predictions, or an INFINITE number of false or true predictions.

Rather, a true theory makes a greater number of true predictions compared to a false theory, or a less true theory. It's the predictions made by the theory by which we test it to determine if it's true or false, or how true or false it is.

AchillesSinatra: "It' [Newtonian mechanics] is not totally false. Because many of its predictions turn out true, maybe most of them. These true predictions can make it a mostly true theory." - Lump


We've been through this before, dude.

Many of the predictions of Ptolemaic cosmology (geocentrism) also turn out to be true.

But just a few pages ago you told us unequivocally that Ptolemaic cosmology is false -- not "a mostly true theory".

AchillesSinatra: "No, he [David Bohm] is saying Newton's is less true than another theory which makes better predictions and therefore is more accurate than Newton's." - Lump


No, dude. Here's the man himself again:



"A theory that has real predictive content must then, as it were, "stick its neck out". But if it does this it is likely in time to "have its neck chopped off". Indeed, this is what did happen eventually to a great many theories such as Newtonian mechanics, which were confirmed up to a point but then shown to be FALSE."

- David Bohm, "The Special Theory of Relativity", pp 149-150 (my emphasis)

AchillesSinatra: You continue to make the same mistake over and over, Lump. That is, confusing the truth/accuracy of the predictions which can be derived from a theory with the truth of the theory itself.


Newtonian Mechanics and Einsteinian relativity are logically incompatible theories. They describe very different universes.

Therefore, the truth of one entails the falsity of the other.

It's that simple.

AchillesSinatra: "He [David Bohm] is not simplistically saying "Newton's mechanics is false." " - Lump


"Indeed, this is what did happen eventually to a great many theories such as Newtonian mechanics, which were confirmed up to a point but then shown to be FALSE."

-- David Bohm (see quote above)

AchillesSinatra: Perspicacious readers may have noticed an apparent contradiction in my recent posts.

"Because scientific theories of a general nature can neither be demonstrated (in the logical sense) to be true nor false." - me

"Newtonian mechanic [was] shown to be false" - David Bohm



Bohm's book is a joy to read; he's obviously an extremely intelligent man. That said, he was writing back in the 1960s, during the period when Karl Popper's falsificationist doctrine still held sway.

Popper's ideas are largely discredited these days die to subsequent developments in the philosophy of science by men such as Kuhn, Lakatos, and Feyerabend.

Can scientific theories be "shown to be false" as Bohm tells us? Ans: No, at least not in any definitive logical sense.

What we can say, though, is that inasmuch as Newtonian mechanics and Einsteinian relativity are logically incompatible theories, anyone who accepts the truth of the latter must -- on pain of logical inconsistency -- concede the falsity of the former. And vice versa.

Lumpenproletariat: Achilles: "The geocentric theory (of Ptolemy) was used -- to great success -- for centuries for purposes of navigation, astronomy, and whatever else, precisely because it yielded extremely accurate predictions. You could get on a yacht right now and navigate to me here in Taiwan using it (cf. Newtonian mechanics getting us to the Moon)."

It's possible that this theory did contain some truth if it really was used for practical predictions as you're saying.

So if that's true, then it had some significant truth to it. But I don't believe you that it really did make significant true predictions as you're describing. Rather, there were other sources for those predictions than the theory that the earth is the center, remaining stationary, while the sun rotates around it, every 24 hours, and also all the stars and other planets etc., in regular rotations or orbits around the earth.

This earth-centeredness was not the theory used by which to make those practical predictions that turned out to be true. Rather, those predictions, or facts about navigation and astronomy, did not rely on the idea of earth-centeredness, but rather on other observations and theories. And someone combined those with a geocentric theory in some way, but the geocentric theory per se was not used to derive those predictions.

But even so, if you're right that a geocentric theory really was used in order to provide such accurate predictions, for navigation etc., then it means the geocentric theory did have some truth in but was replaced by later heliocentric theories which did still better at making the predictions.

You expect everyone to believe you that reliance on earth-centeredness was necessary for those purposes, and that navigation would have been impossible without geocentrism to give the necessary information for navigating, and I don't believe that. The information used for those practical purposes did not rely on geocentric theory but on other sources.

________________

"One of the reasons the heliocentric theory (Copernicus) won so few converts for decades after its appearance was because the predictions derived thereof were not appreciably superior to that of the geocentric theory."

Maybe at that time it was difficult to do the necessary tests.

If there's no way to test it, then there's no way to know if the theory is true. So it's only later when it could be tested that it could be determined that it was a better theory.

The fact remains that it's only in the testing, to see if the predictions turn out to be true, that any theory is shown to be true. It's the reliability of the theory to make correct predictions which makes it a true theory, or a truer theory than another theory.

AchillesSinatra: "You expect everyone to believe you that reliance on earth-centeredness was necessary for those purposes, and that navigation would have been impossible without geocentrism to give the necessary information for navigating, and I don't believe that. The information used for those practical purposes did not rely on geocentric theory but on other sources." - Lump


This is a good point. Clearly the Polynesians, say -- master navigators -- were not relying on Ptolemaic theory as they pursued their diaspora across the Pacific islands.

It's kind of orthogonal to the point I'm making, though. Extremely accurate predictions CAN be derived from Ptolemaic cosmology, even if certain people are unaware of them.

Plug into Ptolemaic theory what Mars, say, is up to right now, and voila! -- the theory will tell you where Mars will be three hundred years from now, with a high degree of accuracy.

AchillesSinatra: "It's possible that this theory [geocentrism] did contain some truth . . . " - Lump


Well, again, you're making the same mistake.

Could Ptolemaic astronomy boast predictive and explanatory power? Yes.

Could phlogiston theory boast predictive and explanatory power? Yes.

We are now told phlogiston does not exist. If that is correct, then the theory contains "no truth" (your terminology) whatsoever.

A theory's predictive and explanatory success is quite another matter from the theory's truth.

AchillesSinatra: re - Polynesians and Ptolemaic astronomy

It's not unlike the case of Halley's comet, the successful prediction of whose return is often vaunted as a great confirmatory success for Newtonian mechanics.

The same prediction could, of course, be derived through simple extrapolation:

1. There was a really bright comet here 76 x 3 years ago

2. There was a really bright comet here 76 x 2 years ago

3. There was a really bright comet here 76 years ago

4. There is is a really bright comet here now.

Prediction (without any recourse to Newtonian theory): It's the same comet and it will be back in 76 years.

Lumpenproletariat: Achilles: "OK, if you did not say that, then you're agreeing with me that:

For any alternative scientific theories, we know which is correct -- e.g. flat-earth vs. round-earth theory -- based on the predictions which either theory makes, and the one which ends up vindicated by testing/experience reality-check is the one which is correct, or is telling the truth."

- Lump



Do I agree? Of course, I don't."



You don't agree that we determine which of the theories is correct by testing them according to the predictions they make, assuming the one giving us more correct predictions is the more correct.


OK, then how do we know the earth is not flat rather than round?

How do we determine which description of it is correct without doing some kind of observation of the earth, by traveling around/across/over it to see what its shape is?

One theory predicts we would fall off the edge, the other theory says we would finally end up back at the starting point, if we keep going the same direction.

And other such observations, based on prediction of what would be observed in either case.

If this is not how we determine if it's round or flat, what is the method used to determine which theory is true?

Has there been some other method of determining the shape of the earth? By saying it's not by making predictions of what we would see, you're implying there is some other method for determining if a theory is true or false. What is that other method, not containing predictions of what is experienced when the theory is tested?


____________

"First of all, "The Earth is Flat" and "The Earth is Round" are hardly what would normally be described as scientific theories. Both claims are simple, singular statements, as opposed to scientific theories which typically have a lot more "meat" to them, and tend to be general/universal in scope. Moreover, both claims go back to antiquity, and the matter was effectively settled by the ancients Greeks, long before anything we might call experimental science appeared on the scene."

That's a cop-out.

Tell us how you know the earth is flat rather than round.

You know the difference. There's nothing unscientific about "round" and "flat." We could use "spherical" rather than "round" -- but why obsess on semantics? We all know what "round" means.

______________

As for for your claim that when two scientific theories are at loggerheads, it is in virtue of the predictions derived thereof that we know which "is correct, or is telling the truth", this is more nonsense, I'm afraid. To claim as much is to fall victim of the well known logical fallacy of "affirming the consequent", viz.

Premise 1: If my theory is true, then [such-and-such] will be observed

Premise 2: [Such-and-such] is observed

Conclusion: My theory is true


The inference is, of course, fallacious -- the conclusion is not entailed by the premises. Any scientist worth his sodium chloride knows this, dude."


There's nothing fallacious in that, assuming you fill in the necessary details for the particular theory and the observations to be made or predicted.

If my theory is "It's raining outside" it means

Premise 1: If you go outside you'll get wet as drops of water fall on you.

Premise 2: You go outside and get wet from drops of water.

Conclusion: My theory is true.

What's wrong with that? What's not scientific about it? There are other predictions also, in addition to the above. But that only means there are further tests which would confirm the theory if it's true.

And it's always possible I might plant someone on the roof to throw water down on you, or even that a water balloon was shot overhead just at that moment by chance, so of course it's possible the theory is false. But probably it's true if the predictions are correct and the observation happens as predicted.

What's not scientific about that?

_____________________

L: "In other words, some practical experiment is done to check which one made the correct prediction, and that one is the true theory (or more true than the other), while the one whose prediction turns out false is not the true theory.

And you agree that this is how we know which theory is true and which one is false, when 2 differing theories conflict with each other. This is how we know the earth is round and not flat. Or how we know that any theory is true or false." - Lump


A: "This is the myth of the "experimentum crucis", or crucial experiment. It goes something like this:

1. Two (or more) rival theories are vying for our attention
2. A crucial experiment is performed.
3. Theory A is shown to be true, or at least confirmed; Theory B is shown to be false.
4. All scientists immediately and en masse recognize this, endorse Theory A and renounce Theory B.

This kind of thing never happens -- the kind of fairy-tale crap we often see in elementary science textbooks notwithstanding. No matter what the outcome of an experiment, there will always be scientists who continue to defend Theory B."

No, not necessarily IMMEDIATELY AND EN MASSE -- no one says that.

You're proving my point. The reason there is usually no unanimity is that there are many experiments and they give contrary results, sometimes confirming theory B because it did better in predicting the outcome, and sometimes confirming theory A because it did better in predicting the outcome.

It's only because of the mixed results in observing the outcomes that there is a mixed response by the scientists.

But in cases where the observations overwhelmingly confirm one theory over the other, in respect to the observed outcomes, based on the predictions of each theory, then there is mostly agreement among the scientists, accepting the stronger theory as being correct.

So again you're agreeing with me that it's the predictions from each theory which are the basis for determining which one is true and which one false, or which theory is more true, or if they are equally true or false. It's all determined by how well each theory performs when its predictions are tested.

And the doubts are due to uncertainty about which theory's predictions perform better in the testing, in the long run. The scientists might hesitate at first, until after one theory performs substantially better than the other over many tests, in many different testing conditions. But it's always the better performance of one theory over the other which finally causes the scientists to prefer that theory over the other. I.e., its better performance in terms of its predictions being more accurate, or turning out to be correct, over many tests, or many trials.

So just because there is uncertainty and non-unanimity at first does not change the fact that it's the testing, based on the predictions, which determines if a theory is true, or is more true than another.

__________________

A: "More to the point, why can there never be a crucial experiment of the kind you suggest? Ans: Because scientific theories of a general nature can neither be demonstrated (in the logical sense) to be true nor false."

Yes they can be. And are.

That smoking causes lung cancer has been confirmed as true, through testing, using predictions of what happens when experiments are done. Such as using mice and other subjects.

Of course there are always some additional doubts which are raised, so that there is never 100% certainty. Only 99.9%. Or 98%. Or 97.93%. It doesn't matter what the exact margin of error is, or how short of 100%.

If it has been confirmed enough times, with enough testing, it's considered a fact, for practical purposes.

There can be no other basis for establishing any scientific facts, about harmful substances in the body, about harmful elements in the air, about climate change, about what causes weather patterns, etc.

You can always say there's more which would require modifying the earlier theory, even though that theory is correct. Even so, it can still be replaced by a newer theory which is better because it performs better still in terms of its predictions.

________________

A: "A theory which appears to sit uncomfortably with certain observations can always be defended by making adjustments to the concomitant "auxiliary hypotheses", or what we might simply call "background knowledge".

I.e., a theory which falls short in its prediction-making ability can be modified as necessary.

All such modifications are based on testing it to see if its predictions are correct. So its still the predictions it makes, and testing them, which are the basis for establishing that the theory is true, or is more true than another, or is false.

MJ59: Boys have a penis, girls have a vagina

AchillesSinatra: @ Lump

If you wish to insist that "The Earth is round" and "The Earth is flat" are scientific theories, then I personally have no problem with the former having been proven (roughly -- it's not quite spherical).

Er, which scientists proposed these theories?




QUOTE (Lump)
There's nothing fallacious in that, assuming you fill in the necessary details for the particular theory and the observations to be made or predicted.

If my theory is "It's raining outside" it means

Premise 1: If you go outside you'll get wet as drops of water fall on you.

Premise 2: You go outside and get wet from drops of water.

Conclusion: My theory is true.

What's wrong with that?
UNQUOTE (Lump)


Ans: There's nothing wrong with it. It's a perfectly valid case of modus ponens. (i.e., If P then Q; P; therefore Q)

Unfortunately, it has not the same structure as your previous . . .

Premise 1: If my theory is true, then [such-and-such] will be observed

Premise 2: [Such-and-such] is observed

Conclusion: My theory is true

. . . which has the form "If P then Q; Q; therefore P". This is an invalid inference known as "affirming the consequent".

See the difference?

MJ59:

AchillesSinatra: "That smoking causes lung cancer has been confirmed as true, through testing, using predictions of what happens when experiments are done. Such as using mice and other subjects." - Lump


Again, I don't have a problem with it (that smoking causes lung cancer). But you're claiming it has been PROVEN.

Is there any possibility that it could be wrong? E.g. perhaps there is a gene that causes both lung cancer and a predilection to smoke. In which case, smoking does not cause lung cancer; both have a common cause.

I'm not suggesting this is likely, but if there exists any possibility that the claim is false, then it has not been proven, in any definitive logical sense at least.

AchillesSinatra: "All such modifications are based on testing it to see if its predictions are correct. So its still the predictions it makes, and testing them, which are the basis for establishing that the theory is true, or is more true than another, or is false." - Lump


Same old.

Scientific theories, at least those of a general nature, cannot be "established to be true".

Are you familiar with the problem(s} of induction?