Kuhn, Feyerabend and Popper; Super Showdown
In the field of epistemology, there are three special actors who will never cease to influence: Thomas Kuhn, Paul Feyerabend and Karl Popper. Each brought their respective doctrines; subjectivist scientism (crassly put), epistemic anarchism and falsificationist realism. These epistemological concepts all painted science in a different light and came in turn to fight bloody battles in the court of ideas for many years to come.
So let’s emulate this battle in the comments. Who do you think has the right idea of what science is? I personally hold Popper highest, I’ll present my arguments as we go along. However, I’d be happy to be convinced of otherwise!
So let’s emulate this battle in the comments. Who do you think has the right idea of what science is? I personally hold Popper highest, I’ll present my arguments as we go along. However, I’d be happy to be convinced of otherwise!
Comments (69)
:D
I wince a little when Popper is called a "falsificationist ". Not because he was not a falsificationist, but because falsificationism is so often misrepresented as naive falsificationism. Popper did after all, in LSD, explain that logical falsification of a scientific theory is impossible. He was however, certainly a "Critical Rationalist" of which "fallibilism" is a central tenet.
What were Popper's main achievements in epistemology? Wasn't he first to elucidate the scientific method? He rehabilitated metaphysics from the Logical Positivists, gave us the criterion of demarcation, and solved the problem of induction. Plenty of other achievements, I'm sure, but I would need to consult a book to compile the list.
It might be worth mentioning that Popper was heavily involved in the intellectual circle that developed the Modern Evolutionary Synthesis, where his epistemology and how genetics works are strikingly similar.
Partly because of the above associations, several Nobel Prize winners in the fields of biology and medicine credit their discoveries to following Popper's method. His ideas have also been central in discoveries in physics and computing. I'm not sure the other epistemologists mentioned could make a similar claim. Also Popper's ideas still seem quite active, in the sense that there appears to have been some progress recently.
One thing is for sure, Popper must be the most misrepresented and most misunderstood philosopher of the 20th century.
"Ought to be" can take a hike as far as I'm concerned.
Aside from that, I'd say "all of the above in many important respects." And part of the reason that it's all of the above is that science is really a bunch of people doing a bunch of different things, where they're not clones of each other.
The problem with Popper isn't that he influenced some people to think differently. That is what good philosophy does, and while I disagree with Popper I certainly think he is a good philosopher -- that is, he is worth reading.
On one angle I suppose I feel frustrated with Popper not because of Popper, but because of Pop-Popper. "Falsification" is a quick and easy word which pop-science writers latch onto without context and use as a kind of universal criterion for scientific knowledge, which is just not the case.
But that is more the result of just not reading Popper, and doesn't have much to do with Popper himself.
More philosophically -- the problem with Popper is the scope of his claims, and the prescriptive nature of his project. He's making a normative project for scientists, and doing so not just for a few scientists who feel inspired but for scientific knowledge as a whole. And while Popper's method gets at some aspects of scientific thought, it does not meet the burden it sets for itself -- and yet still demands that science should be performed in accordance with his particular epistemological concerns.
Feyerabend demonstrates this by placing Popper's method alongside Galileo's Dialogue Concerning the Two Chief World Systems -- an example which surely everyone would agree is properly scientific, and even good science, yet does not follow Popper's method. So either Galileo is wrong about how to do science, or Popper has overstated the scope to which his method applies. (at least, if we agree with Feyerabend's analysis, of course -- we could set out to save Popper by trying to reframe Galileo in Popperian terms. But I'm fairly well convinced by the arguments in Against Method)
I can give a rough picture of his account, though it will be lacking on detail.
Scientific progress is often characterised as an interlinking between theory; which generates propositions about the world; and experiment; which tests those propositions. This basic picture is correct.
Testing, as Popperian falsification is typically characterised in the following way: a proposition about the world is posited, an experiment either refutes or is consistent with that proposition. But this does not describe the activities of reasoning that science consists of very well at all. Consider the cases of the discovery of Neptune and the precession of Mercury.
In Neptune's case, Newtonian mechanics was applied to the orbital behaviour of another planet, Uranus, and it was found not to describe it very well. At this point, other astronomers posited the existence of another planet whose gravitational effects fixed those predictions; the planet who fixed those predictions was discovered where it was predicted to be, and Newtonian mechanics was vindicated.
In Mercury's case, Newtonian mechanics was applied to Mercury, and it was found that there was a deviation from the predictions. Scientists were reluctant to put Newtonian mechanics in the bin since it had been so successful, and instead posited that the astronomical measurements which established the deviation from the theory instead were in error. More precise measurements came along and vindicated that Mercury's orbit was not exactly predicted by Newtonian mechanics. Eddington's question to Einsten, then, made Einstein (and his wife!) go through all the tensor calculus required to predict the orbit of Mercury with his theory, and it was found to match the astronomical measurements. In this case, then, Newtonian mechanics was found to be wrong, and Einstein's theory supplanted it in some relevant sense.
What these cases show is the role of auxiliary hypotheses and hard cores in the process of scientific reason. We have a 'hard core' of a theory, which is constituted by its necessary commitments, and we have a belt of 'auxiliary hypotheses' surrounding that hard core which provide the interface of that hard core with experiment. The hard core in the Newtonian case was (roughly) the three laws and their associated calculus, especially Newtonian gravitation - and auxiliary hypotheses were observations, calculations and predictions about the motion of bodies; especially planets and their orbits. In the both cases, an auxiliary hypothesis was posited to protect Newton's theory of gravitation from refutation. In the case of Uranus' orbital measurements, this was that there was another planet which accounted for the deviation. In the case of Mercury's orbital measurements, this was that the measurements were of poor quality.
Let's pause at this point to highlight something important. Newtonian mechanics and Einsteinian mechanics required extra assumptions to interface with the real world; these were measurements of mass, orbital position and so on; the theories themselves made no specific predictions about the real world without having these other auxiliary hypotheses to provide grist to their mills.
Back to the account, we're now in a position to distinguish Lakatos from Popper in terms of falsification. There are two big differences.
Firstly, Lakatos characterises falsification as operative not on singular propositions, but on series of propositions. Such a series might be 'The laws of Newtonian mechanics + observations about Uranus' orbit' or 'The laws of Newtonian mechanics + observations about Mercury's orbit', and when falsification strikes (when 'Nature shouts "No!" as he puts it), it does not act on a specific proposition, but on the composites "The laws of Newtonian mechanics + observations about Uranus' orbit'. The composites are treated in the sense of logical conjunction, so when we falsify "The laws of Newtonian mechanics + observations about Uranus' orbit', we de Morgan's law it up and negate a single set of conjuncts. In the Uranus+Neptune case, the negation operated on the existence of relevant celestial bodies, in the Mercury case, the negation first was thought to operate on the measurements of Mercury's orbit then when they were shown as good, it operated on the hard core of Newtonian gravitation.
The habits of scientists, then, are when Nature shouts no, they prefer to reject an auxiliary hypotheses and posit a new one rather than reject some part of the hard core. This is what makes the hard core 'hard' - it is refutation resistant in the practice of scientists - whereas the auxiliary hypotheses are the easier candidates for refutation.
The second difference from Popperian falsification is that the rejection entailed by Nature shouting 'No!' is weakened. We don't reject Newtonian mechanics entirely just because it fails to model the orbit of Mercury, we rather constrain its application to a domain of relevance, and this is done adaptively with respect to theoretical and experimental demarcations. So we actually maintain belief in falsified propositions by continuing to use the theories, though with a restricted domain of relevance.
This emphasis on sequences of theories means that Lakatos thinks science does not consist of a linked series of singular propositions subject to experimental refutation, it instead consists of a transforming sequence of hard-cores and auxiliary hypotheses over time, and temporally demarcated hard-core + auxiliary hypotheses composites are termed 'research programs'. It is research programs which are the active unit of science, not propositions and their falsifications; for it is research programs which modify theories, make predictions, reject propositions, and change hard-cores.
This, then, gives an account of scientific revolution; rejecting a hard core, as in the case of Mercury, yields a novel research programme, Einsteinian mechanics. But in distinction to Feyeraband, these research programs are not incommensurable; they do not differ in terms of a conceptual scheme; they can differ in scope of application; and scientific inquiry admits research programmes that, strictly speaking, have contradictory hard cores. Simply because research programmes have a native context of application in which that hard core makes sense.
The relationship between hard cores and auxiliary hypotheses also gives a vantage point from which to view the demarcation problem; what is the difference between pseudoscience and science? Lakatos treats this as a condition of scientific practice; as a property of a research programme; rather than simply turning on the falsifiability of propositions. He also gives a practical account of what it means to treat a hard core as non-falsifiable.
As seen with the Mercury example, scientists can adjoin an auxiliary hypothesis to block rejection of the hard core. If a research programme routinely does this, when their research consists mostly of positing auxiliary hypotheses to protect their hard core, that research programme is called degenerate. When they are not degenerate; when science is progressing through the research programme; they are called progressive. The science/pseudoscience distinction is then transformed to the progressive/degenerate distinction, and from the relationships of singular propositions to falsification to the relationship of research programmes to their propensity for non-rejection of the hard core through the perpetual creation of ad-hoc auxiliary hypotheses. Freudian psychology and Marxism have this character for Lakatos as they do for Popper, though for much different reasons which we have discussed.
What sort of prescriptive things do you not like? The requirement to be open to criticism, and to subject one's ideas to the harshest of tests? How a bout the requirement to not appeal to any authority, or that a scientific theory must yield testable statements about reality?
There are more subtle requirements, like given the choice of two theories, one should choose the one with higher empirical content, because it will be more falsifiable. Also, that falsification is itself subject to error (we are fallibilists after all) so any such decision must be regarded as tentative, so theories and their criticisms are never completely discarded.
Of course, this is only a superficial account, but these ideas seem rather good to me.
Complaining about the Scientific Method is like complaining about Evolution.
Quoting Moliere
As is common in most misunderstandings of Popper and the Scientific Method, is the misconception that Popper provides rules for solving problems or constructing theories. He does not, because there is no such thing. Popper's Scientific Method deals solely with how we must treat and criticise theories, not how we come by them.
All of the above! Things should certainly be immune to criticism, and easy tests are far superior. Authority should reign supreme, and testable statements about reality are bunk.
:D
Actually, I am hesitant about "Must yield testable statements about reality", though I am responding with sarcasm here.
More seriously: generally speaking, I don't feel keen on prescriptive theories of science at all -- that science should fit a philosopher's conception of knowledge for his particular concerns about knowledge is just too a priori for me. I prefer a more historical, and therefore empirical, approach to understanding the beast called science.
Quoting Inis
Feyarebend uses this requirement with respect to Galileo. If you haven't read Feyerabend then I'd really recommend it. He was, after all, heavily influenced by Popper. He knew what he was talking about.
Quoting Inis
They do! The only problem is that they do not resemble how science is actually done in a universal sense.
Popper confronts and solve the Duhem-Quine Thesis in "Logic of Scientific Discovery".
Quoting fdrake
According to Popper, falsification of any theory is logically impossible.
Quoting Inis
Ok!
It's exactly how all new theories are treated in Science. There is no other way to the truth.
It's literally in the book, and I would provide an exact quote but there is a 4 year old sleeping in the room where the book is. Look it up!
I'll wait on you providing the reference later, then.
I tell you what, in the absence of a block function on this forum, please never interact with me again, and I will pay you the same courtesy.
Thanks for the reference. Please notice that I attributed to Popper the idea that falsification obtains of singular propositions rather than scientific theories. And explicitly contrasted that to Lakatos. Falsification works as a demarcation criterion, but in practice things are different, we don't throw the baby out with the bath water. Lakatos starts from not throwing the baby out with the bathwater, and attempts a descriptive account of science from there.
I don't think that Feyerabend is quite so anti-knowledge as you're putting it. Rather, his stance is one that emphasizes a multiplicity of ways of knowing, rather than having some arch-method by which we can designate good from bad knowledge. His epistemic anarchy or dada-ism has more to do with a hesitation to generate a general theory of science or knowledge as a whole than it does in being against knowledge.
What he undermines is not knowledge, but universality or hierarchy of knowledges where there is a queen of all knowledge. The phrase "anything goes" is one which describes his universal theory of knowledge -- or, in a way, is just a way of saying there is no universal theory of knowledge or a queen of knowledge.
But that doesn't mean we know nothing.
Couldn't be further from the truth.
Popper will be underestimated for a thousand years.
This is a banality.
The ideas that are popularly credited to Popper have been around since Bacon. What is right about Popper's prescriptions isn't new or radical at all.
I'm not so sure this is an accurate characterisation of science, or quite captures Popper's central ideas. Let's not forget that Freudian psychoanalysis still exists, as does the Copenhagen interpretation. Also, the Sokal affair, and the more recent Sokal-Squared debacle in the Social "sciences".
I suspect Popper might have some advice for String theorists too. His method is much more iterative, focusing on identifying specific problems that need to be solved, rather than the all-or-nothing grand-plan approach of their research program. Ironically, the earliest developments in String theory came about by focusing on specific problems.
It is interesting to note, that the floundering efforts to unify physics may be rescued by an avowed Popperian. See the recent papers by Chiara Marletto
https://arxiv.org/search/quant-ph?searchtype=author&query=Marletto%2C+C
Popper's account of science is much more akin to the struggle to find good realist accounts of what exists in reality, how it behaves, and why it does so.
Hrmm? I don't think I said anything about intent, or that he was multiplying knowledge -- only that his approach isn't anti-knowledge, but rather against some over-arching methodology which characterizes science universally. Something like Popper's project, in fact, as that's exactly who he's responding to.
What if there is no specific set of criteria that captures all science? Wouldn't it be more honest to not describe it if that were the case?
Quoting Pelle
I guess the response here is -- so what? If someone wants to run a research program on Marxist Science, Creation Science, and Astrology, who cares? I can tell you the specific reasons why I don't believe in this or that set of beliefs. But there's no reason to have an over-arching theory of knowledge to safeguard the sanctity of academia. I can respond in kind to any sort of research program or argument.
Creation science, for instance, can be best characterized by William Dembski, I think. I can go through his paper and I understand the argument and I understand why I disagree with it, rather than simply say "well, he's a creationist, and so it is not scientific, and so it is unworthy of academia, and so it is bad" -- putting him to the side without ever engaging him. I don't really care if he has a research program. What harm could possibly come from it?
As far as I'm concerned science is about having fun exploring questions and answers. Once you lose that then it's just another day job with a little bit more math thrown in.
There is: The Criterion of Demarcation.
Quoting Moliere
This would be against the Scientific Method, and ruled out by the criterion of demarcation.
And as a true Popperian you reject authoritative sources of knowledge, certainty, and anything that claims to beyond criticism.
He really didn't just invigorate old ideas. They were his ideas and they were so radical, that still very few understand him.
Usefulness is a dangerous cudgel. For one there are many pursuits whose fruit are only born on the wave of seemingly useless inquiries -- consider philosophy, the study of foreign language, history, art, or even many of the sciences. There are scientists who study some phenomena not because it relates to the cure for cancer, better batteries, more incredible bombs, or more efficient processes but simply because it interests them. Anything useful is appended after the fact as an act of justification to appease the masters of utility that hang their crosses around academia.
Further, usefulness is relative to a group. Marxism or creationism are useful to Marxists and creationists. And naturally, should they gain power, they wouldn't find the bourgeois or atheist sciences terribly useful. Should they be allowed to ban them on this criteria of usefulness?
I believe they'd even be able to provide arguments that their work is, in fact, falsifiable while the work of bourgeois scientists and atheist scientists is mired in the preconceptions they are unable to let go of and is really just an elaborate way to emphasize their own bias.
Then, for two, what's better is for people to simply be motivated by curiosity and to explore questions.
Science is about a lot of things aside from problem solving, and there are many other subjects that don't fall into its purview which also get funding. If research institutions are to be free then it seems to me that usefulness, and other criteria, are just cudgels to exclude said freedom. Reason, in all its fallibility, is good enough to sort out bad arguments. We don't need criteria to sort out the pure from the impure.
I take it that here you'll refer me to my copy of LSD? :D
But you can answer the question too. Suppose the criterion of demarcation does not hold, and not only that that there is no such criteria. What would be the more honest approach? To invent a more elaborate theory of science with better fidelity, or to point out that there is no such theory?
Quoting Inis
I think this sets out a beautiful example of just how the criterion of demarcation works in practice. We have the pure and the impure, and the impure? We need not consider them.
But I would say that good old fashioned arguments are good enough to sort out the good and the bad, and we don't need some criteria to say which is worthy and which is not worthy of our consideration.
Which isn't to say we need to consider everything. We could just not be interested in it. But that's a different stance than from one on high.
I didn't say all of Popper's ideas about science were banal - some of them were just wrong (kidding!) No, I was referring to ideas like "people trying to falsify eachother's theories" and other pop-Popperianisms that some people, including scientists, swear by. Popper's actual lasting impact on the philosophy of science is far more dubious than his rock-star fame would suggest.
Popper, who is deservedly admired, set out a logic for science that is pretty neat. But the problem with logic, as Feyerabend showed, is that people are only occasionally logical.
There is a gap between what is true and what is believed. Into that gap can pour all manner of oddities - ad hoc, ad hom, add whatever you like. Scientific method cannot be cleanly logical.
And that's one issue with Feyerabend; incommensurability.
Davidson's argument against incommensurability, in On the very idea of a conceptual schema, shows that research programs or paradigms or whatever you wish to call them are not incommensurate. You and I might take that as read; others will doubtless disagree.
But the more general point of the distinction between belief and truth made above, still holds.
If we were to apply Feyerabend’s doctrine of science to the academies however, we would have a problem. The poor scientific performance of these pseudoscientists could be rationalized by ”pluratiy of method” and ”anything goes”. Science would infected by improductive forces. That is my primary concern.
Also, I feel as if you’re being very uncharitable about what could be considered useful. In my opinion, anything that brings us closer to the truth is fundamentally useful, which includes philosophy, language study and the Humanities.
Before Popper's criterion of demarcation between science and non-science, the prevailing wisdom was that of the Vienna Circle. The Logical Positivists distinguished between science and nonsense via their criterion of meaning.
Popper not only demarcated science this way, but in the process rescued metaphysics.
There is no sense in which Popper's criterion of demarcation "does not hold". You can only be on one side of it or the other, though you can be mistaken about which side you think you are on.
No he didn't. Popper argued that it is logically impossible to verify or falsify a scientific theory. He sets out a Method, based on certain epistemological truths he discovered. That's why it's called the Scientific Method.
Nevertheless, there is an asymmetry between verification and falsification when it comes to universal statements, and this is what he exploits in his method.
Charles Sanders Peirce spelled out the scientific method (as outlined here) the year after Popper was born.
Where does "A" come from?
A well-prepared mind. Again, Peirce called it a conjecture long before Popper did.
OK, so accepting, for the sake of argument, that given a scientific problem, we manage to retrodict a solution, what are the "reasons to suspect" that A is true. Can you give an example?
As stated in the other thread, the observed (and surprising) fact C is a conclusion that deductively follows from A. In Peirce's own words, also from 1908:
Peirce's favorite example was Kepler's series of hypotheses regarding the orbit of Mars. After only a few unsuccessful conjectures, he tried an ellipse, which not only fit the data that he had from previous observations, but also led to predictions that were subsequently corroborated by further observations.
I'm not sure that it's because of Popper. I'd say it's just because of argument.
Quoting Pelle
Is it a doctrine of science? I don't think that's quite right. In a sense, yes, but also it's a description of science at the most general level. There is a sense in which Feyerabend argues science shouldn't be so constrained as it is now. And the counter is the point out some fairly uncontroversial examples of non-scientific thinking that could then be part of the academy. But my thought is just -- so what? For you, at least, your concern is about productivity. I'll respond to that below.
Quoting Pelle
It's more that "useful" is a group-relative evaluation. Useful could be construed broadly, and it can also be construed narrowly -- but it's certainly relative to whatever goal or value a group or person happens to hold. Though "use" isn't Popper's criteria, so I don't think he falls to such a criticism. For him it's simply that his prescriptions don't mimic obvious examples of productive science, so his prescriptions need to be more limited than what he sets out. But if that be the case, then he hasn't answered the question of the criterion which he set out to answer.
I suspect the question he sets out for himself is not answerable really, at least for the standards that he sets for himself. "Science" is one of those things that can't be crystalized into a method because it is a human activity which includes novelty, human emotion, and so forth. It's often more like an art than a science, except we call it science because of its dedication to clarity, precision, empiricism, and other broad values of knowledge production where art has no such commitments (and it need not to). It may not be exactly like a family resemblance term, but "science" does seem like a family resemblance term.
I guess Feyerabend was right that there is no single exception proof method to follow which will always yield scientific truth, but perhaps this is because to access the information contained at different scales of time, distance, and complexity, we must develop fundamentally different scientific and empirical approaches at the outset? (e.g: cognitive science approaches vs astronomy approaches vs engineering approaches vs medical science vs computer science vs mathematics vs archeology/history vs chemistry vs evolutionary biology vs any number of fields within physics...). Not only do the physical steps we follow to initiate discovery change from field to field, but sometimes the guiding epistemic principles themselves change (e.g: physical sciences are able to rely on prediction-testing while the more human scientific fields, such as statistics, archeology, and computer science, tend to rely on corroboration and agreement with previously established facts as a gold standard). In some cases, such has human behavioral science, discovery can come from something so basic as "black-box testing", where all we care about is the relationship between output and previous input).
It's interesting he should say there is no "useful" exception free definition that universally applies, because utility or usefulness (toward scientific discovery) is exactly what the proponents of each scientific field or school use to guide the development of their own methodologies. Empirical utility in and of itself seems to be the very metric by which we determine whether or not something is scientific (is it precise? is it robust? Does it give us reliable knowledge?).
Depending on the object or field of study, any number of extraneous apparatus, previous work, and established protocols might be required to get anywhere empirically, and in another field the established methods might be entirely different. The sort of free-market of ideas and researchers naturally diverge as they more successfully adapt to their empirical niche. There's a world of variation out there, and it requires varied approaches to decipher it all...
It is a matter of judgement whether a statement is falsifiable or not. Some people think Freudian psychoanalysis is non-falsifiable, others disagree.
Despite what is claimed for the principle of demarcation, and I am as guilty as anyone, it is not really about deciding what is science and what is not. Such questions can be left to the institutions. Rather, in Popper's words, it is to solve,
So really it is about what sort of statements are amenable to empirical investigation. These are the falsifiable statements.
And I think it logically impossible for true ideas to be false.
Well, trial and error can certainly work when trying to figure out the shape of orbits, but lets have a more recent example.
You are doubtless aware that the orbit of Uranus did not seem to agree with Newton's law of gravitation, so we have:
C=Anomalous orbit of Uranus.
A=Neptune is retrodicted to exist, which would make C "unsurprising".
Therefore we have "reason" to believe "Neptune exists" is true.
Is that a fair representation of Pierce's method?
I imagine this 'necessarily consequent upon the circumstances of its occurence together with the truth of the credible conjecture, as premises" might work quite well for engineering or physics, but it doesn't precisely characterise the generation of credible conjecture in statistical applications. Rather, 'plausibility' looks more like high conditional probability, so instead of following with necessity it follows from high (subjective) probability as determined by competence and intuition of the researchers involved and of the complexity of the issues involved in the interpretation of C.
Yes, the hypothesis that Neptune exists (A) would make the surprising anomalies in the orbit of Uranus (C) a matter of course; therefore, we have reason to suspect that Neptune exists.
Quoting fdrake
Immediately after what I quoted previously, Peirce added that "this acceptance ranges in different cases--and reasonably so--from a mere expression of it in the interrogative mood, as a question meriting attention and reply, up through all appraisals of Plausibility, to uncontrollable inclination to believe."
And by the same logic, we have reason to believe the statement "Vulcan exists", is true?
Yeah fair enough then.
What is the observed surprising fact that would be a matter of course if Vulcan exists?
The anomalous orbit of Uranus/Mercury becomes normal when the statement "Neptune/Vulcan exists" is true, which gives us the good reason to believe that "Neptune/Vulcan exists" is true.
Except Vulcan doesn't exist.
The existence of Neptune/Vulcan was a valid retroduction--a plausible explanatory hypothesis for the observed (and surprising) anomalies in Uranus's/Mercury's orbit--but again, that is only the first step in any scientific inquiry. The second step was deduction, deriving other necessary consequences of the hypothesis. The third step was induction, making additional observations to ascertain whether those predictions were corroborated or falsified. In the case of Neptune, they were corroborated (repeatedly). In the case of Vulcan, they were falsified, resulting in abandonment of that particular hypothesis.
Lets get this straight:
1. You retrodict Neptune/Vulcan.
2. You deduce consequences from the retrodiction.
3. You induce corroborations or falsification.
OK. So, given that we have an induced corroboration and falsification of the deduced consequences of of a retrodicted hypothesis in the attempt to justify a theory. What do we do next?
"Retrodict" is not a word. We hypothesize the existence of Neptune/Vulcan.
Quoting Inis
"Induce" usually means "cause." We conduct experiments and/or make additional observations to evaluate whether the necessary consequences of the hypothesis actually come about. If so, then the hypothesis is corroborated; if not, then it is falsified.
Quoting Inis
We continue evaluating the hypotheses, eventually adopting the corroborated one (e.g., Neptune) as a belief and abandoning the falsified one (e.g., Vulcan).
So you retrodict/deduce/induce that the theory that predicts Neptune is true?
Again, we adopt the belief that Neptune exists, because the hypothesis that Neptune exists not only explained our initial anomalous observations, but also resulted in predictions that were corroborated by subsequent observations. We then maintain that belief unless and until we have good reason to doubt that Neptune exists.
So, is the theory, that predicted Neptune true or not?
I currently have no good reason to doubt that Neptune exists; that is, I believe that the proposition "Neptune exists" is true, where "Neptune" designates a gas giant planet with an orbit outside that of Uranus. As Peirce once put it, "Let us not pretend to doubt in philosophy what we do not doubt in our hearts" (1868).
Do you have good reason to believe the theory that predicts the existence of Neptune to be true?
I stand by my previous answers. Perhaps you should clarify exactly what you mean by "the theory that predicts the existence of Neptune"; or better yet, just spell out whatever point you apparently want to make.
That would be Newton's gravitation. Without it, what does "anomalous orbit" even mean?
By the way, Newton perhaps has been given more credit than he really deserved. The laws were already discussed in his circle; all he did was to undertake the task of giving them a mathematical framework, as a holiday project. Newton was the real Sheldon Cooper; and his colleagues let him take the credit in return for doing all that boring math.