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Does Newton’s First Law of Motion assist in validating induction?

The Principle of Uniformity holds that the events of the future will resemble those of the past. That principle underpins the inductive method.

Compare the Uniformity Principle to Sir Isaac Newton’s First Law of Motion:

A body remains at rest, or in motion at a constant speed in a straight line, unless acted upon by a force.

(Per Wikipedia). This statement describes the Uniformity Principle, at least as the First Law describes the predictable behavior of the physical world. Because we know the speed and direction of a body in the past, we know what the speed and direction in the future, assuming no interference from an outside force.

But as far as I know, David Hume took no notice of Newton’s work, nor has anyone else used the First Law for this purpose. Have philosophers missed an opportunity here?

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    Hume very much took notice of Newton’s work, so much so that he fancied himself the "Newton of psychology". However, as far as uniformity goes, "unless acted upon by a force" is the kind of stipulation that consumes the supposed rule. "No course of action could be determined by a rule, because every course of action can be made out to accord with the rule", as Wittgenstein quipped, for a force could have acted. And that just means that this is not a rule that can be used to argue uniformity.
    – Conifold
    Feb 14, 2023 at 5:58
  • Obviously Newton's laws are not examples of induction: no one ever observed a perfect inertial motion. Feb 14, 2023 at 9:31
  • In a broad sense, very "effort towards knowledge" presupposes the Uniformity of Nature, irrespective of a purported "inductive method". Having said that, we try to have knowledge also of e.g. historical events, were there is no reason to assume that "future events of the future will resemble those of the past. " Feb 14, 2023 at 10:21
  • @MauroALLEGRANZA If Newton's laws are not examples of induction (which I take here just as meaning "generalized from observation"), what type of reasoning did Newton use to arrive at them? Also, "perfect" is not needed for induction, IMHO. Physics is nothing but a bunch of approximations anyway.
    – Frank
    Feb 14, 2023 at 15:01

6 Answers 6

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No, your suggestion is a red herring. The UP refers to the tendency of humans to draw conclusions based on prior experience. If I have been stung when approaching a bee-hive, I will assume that approaching another hive might result in my being stung again. If eating a particular type of mushroom makes me ill, I will avoid eating similar mushrooms. And so on. Importantly, Hume considered the point that we make these inferences even though there is no guarantee they will be true- I might approach another hive without being stung and I might eat another mushroom without being ill- so the inference is not justified by inviolable rules of any sort. You should now see that Newton's first law, which is an inviolable rule as far as we know, is beside the point.

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Newton's law applies to massive objects like bowling balls and bullets. It does not apply to ideas, opinions, prejudices or beliefs possessed by groups of people.

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  • @MauroALLEGRANZA Niels is claiming the question is about 'Netwon's Laws' and not Netwon's Laws, perhaps even suggesting there is no such thing as Netwon's Laws particularly in light of possibly 'Einstein's Laws' and, well, Einstein's Laws.
    – J D
    Feb 14, 2023 at 18:07
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For those who believe that science or knowledge of the natural world comes from induction, Newton's laws are themselves justified by induction. Therefore Newton's laws can't very well be used to justify the logical principle that justifies them.

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  • +1 because this is the best prima facie argument presented. I would encourage you to mind the use-mention distinction. Both 'Newton's laws' and Newton's laws are indeed used to justify the metaphysical principle of uniformity. That's because doing induction and justifying induction with words are not the same activity. Thus, your argument rests on an equivocation of induction with 'induction'.
    – J D
    Feb 14, 2023 at 18:27
  • The principle of uniformity is a good conclusion given the practical success of so many scientific laws in general. How do we know the universe is a place replete with patterns and consistency? Because our sciences are so good at predicting. Thus, uniformity is the best sensible metaphysical conclusion when debating the nature of time and space and the success of science at explaining physical phenomena.
    – J D
    Feb 14, 2023 at 18:31
  • Hence, Netwon used induction to generate the linguistic artifacts of his laws, and Whewell used the success of linguistic artifacts of laws to argue Hume's scandal of induction can be minimized by the metaphysical property of the universe, it's regularity.
    – J D
    Feb 14, 2023 at 18:32
  • @JD, neither occurrence of "induction" in my answer is a mention of the word, and neither occurrence of "Newton's laws" is a mention of the phrase. Furthermore I don't see how a phrase can be used to justify a metaphysical principle, nor do I understand how you think the metaphysical principle of uniformity is different from the principle of uniformity. The difference between doing induction and justifying induction is obvious, and I don't see why you think the existence of that distinction creates any sort of equivocation in my answer. Feb 14, 2023 at 20:04
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Hume treats the uniformity of nature as if it were an ordinary inductive principle. What he misses is the fact that experience frequently seems to falsity it and yet we do not necessarily abandon it. When we come across an apparent violation of a generalization uniformity, we have several courses of action short of abandonment, only one of which he recognizes.

We can look for circumstances that differentiate the problematic case, showing that our generalization is not contradicted. (Hume calls this “a secret cause”.) We can modify our generalization by, say, extending its scope. Thus, water does not always boil at 100 Centigrade, but we elaborate the rule to include an additional variable (air pressure). Again, fire does cause burn injuries, but it is not the fire that burns, it is the heat, so cooler things than fire can burn; and acid causes similar injuries. Finally, we can simply park the new case as an unsolved problem - an anomaly, Kuhn describes it. We might abandon the generalization, but only as a last resort.

The Uniformity of Nature tells us when we have a problem and implies how to resolve it. It is not exactly like an axiom or presupposition. It is more like the outline of a research programme.

Newton’s Laws of Motion are equally not inductions. Newton could only have observed a body not affected by any external force in a universe consisting of one body excluding the observer. Nor could he have established or falsified the other laws by observation. In any case, we did not abandon them when we found circumstances in which they do not apply; we simply limited their scope.

These laws are more like axioms, not because they are self-evident, but because they are conceptual (grammatical in Wittgenstein’s sense of the word). They define what a body is. The first one tells what we do not need to explain, and hence what we do need to explain. The other laws are also not inductive. They define a framework of explanation. Lakatos’ idea of a research programme is useful in understanding their function if we regard them as a research programme designed for, and defining, a specific domain.

The principle of the uniformity of nature and Newton’s First Law are similar in some respects, but have different scopes. They don’t assist each other, but then neither needs any assistance from the other.

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Boy, so many cantankerous responses to a seemingly reasonable question!

IMNSHO, Gudeman comes closest to raising the central philosophical issue, though his response favors a foundationalist approach:

For those who believe that science or knowledge of the natural world comes from induction, Newton's laws are themselves justified by induction. Therefore Newton's laws can't very well be used to justify the logical principle that justifies them. - David Gudeman

A foundationalist certainly would have a problem as a linear thinker of accepting the circularity inherent in the process. The way to derail the argument of the foundationalist is simply to invoke the circularity inherent in languages and metalanguages (an explanation of which is outside the scope of this response). Needless to say, I would argue the automatic rejection that your question doesn't presume foundationalism (at least in the simple form presented) doesn't ultimately destabilize the concern the imputation that the laws (the linguistic artifacts used to communicate the concepts that are consistent empirically according to a correspondent notion of truth between word and state of affairs) do indeed endorse induction and ultimately principle of uniformity because:

  • They are instantiations, applications, reifications, or particulars that do work and hence endorse the principle by providing part of the semantic extension to ground the principle in.
  • They are functional. That is, the laws are used by physicists succesfully thus showing that the inclusion of them as part of the semantic grounding of the thesis that is the principle are not inconsistent and meaningful. This would be more of a coherent approach to deciding the truth. Obviously, if some laws refuted the principle and some laws physicists used endorsed the laws, the principle itself would have consistency issues.

Why it all works, as far as I can tell, is that the principle itself is inferred from the variety of laws that are successful in the first place. So within the historical context, the principle was put forth as a universal, abstraction, generalization, what-have-you of so many meaningful principles that can be shown to be empirically adequate. Netwon came before Whewell, the coiner of the then-neologism, by more than a hundred years, I believe. It seems to me that Whewell, a 19th century philosopher of science would have been familiar with Newton's impact on science, right?

Now, my response presumes a certain familiarity with the theories of truth, and I would just suggest any answer you take under consideration simply considers, as Niels Nielson has suggested, that one applies use-mention distinction when appraising what is meant by 'laws of science' when and in what context, and that one doesn't mix up the various theories of truth applied during the analysis.

I think this is an excellent question because it's sort of intuitive that human beings USE inductive logic long before they can explain what it is. That's not a paradox because explanation is linguistic use, and usage is linguistic mention as accepted generally by analytical philosophers.

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Newton's first law of motion is:

if there is no net force on an object it will be at rest or in uniform motion in a straight line.

However, once we realise that uniform motion can only be detected with reference to another object, we see that Newtons first law simply says that:

if there is no net force on an object then it will be at rest.

This is Aristotles law of motion. And historically this is how it developed: from Aristotle to Philoponus to Avicenna & to Newton.

Now Aristotles law of motion is derived from his law of change and this is essentially a tautology. So the uniformity principle or induction has no real bearing on how Newton's law developed.

Induction, however, has a large bearing upon science. Poincare declared that induction held the higher ground over deduction in mathematics and this goes for science too.

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