Induction and Science

You are still not responding to the problem. Newton's law of gravity is a statement about forces of attraction between bodies. None of the astronomical observations used for evidence was about forces of attraction. Therefore Newton's law of gravity was not a generalization of those observations, so it could not be a case of induction.

Deduction is an abstract symbolic process. Measurement is a physical process.

How can I not be responding to a "problem" that you have only just brought up ?And your "problem" is easily answered by anyone who has a basic knowledge of the physics involved. An orbit involves continuous acceleration towards the centre of the orbit - Newton's laws of motion tell us that. So if one body orbits another there is a force attracting the orbiting body to the body that it orbits.Indeed I have to ask if you actually considered the question of how the astronomical data was relevant in the first place you would have to realise that gravity was involved somehow and that any claim to the contrary could not be true.So now I've responded to the non-problem that you raised, why don't you produce your alternative method ?

...which proceeds from comparison to an assumed, axiomatic standard. In other words, when we measure, we're taking it as a given that a meter really is a meter, etc.It caught me off-guard as well, but Rrhain is right on this one. Measurement is deductive, as it is a form of reasoning to the specific - this object is 1.2 meters in length - from a general axiom assumed to be true - a meter represents such-and-such distance.

Well to take the case of General Relativity. Einstein deduced it from symmetry arguments and facts about Riemannian geometry as well as general thoughts about the inertial quality of orbiting frames.From this he deduced the Field Equation, which was then confirmed experimentally.Nowhere along the way was there anything I'd truly call induction, or at least solely inductive reasoning.Similar cases apply to QED, QCD and the Standard Model. To a lesser extent than GR though.Most of physics, particularly condensed matter physics, in the last fifty years has been what I'd call deductive.

A lot of it may be largely deductive now, but I thnk that you will find that it requires a basis of empirical evidence to start from and further, confirmation will still be inductive in nature.There is no theory in science that does not involve some givens that have to be derived from empirical evidence. And how can we say that these givens truly apply to the whole universe, without some use of inductive reasoning ?Indeed it should be pointed out that somce scientists are working on revising GR as an alternative to "dark matter" theories to explain gravity formation. Or we could simply consider Einstein's irea of a csomological constant, his abandonment of the idea and the recent revival of the concept. Abduction and induction play a part even in GR.

I have been asking and you have avoided answering this question since Message 60. I just reworded it. In order to derive statements about force of attraction, statements of the form that the law of gravity is said to generalize, you would first require

• Newton's law of gravity;
• The results of the Cavendish experiment done about 111 years later.

The law of gravity could not have been merely an inductive generalization from the observations available to Newton.

You have allowed yourself to be misled by Rrhain's argument.I can do deduction in my head. I can't tell the temperature in my head - I need a thermometer to do that.

Yes, I agree.Einstein was, of course, informed by experimental data. But deriving GR was mainly theoretical. For Newton, there was a large theoretical component, too. He had good reason to have invented calculus.

On rereading your Message 60 that specific question is not there. Therefore your claim that I am dodging it is false.Your attempted response also fails to deal with the issues I raised.Nor do you provide any reason why Newton would have needed to work out the law of gravity before considering the observational results available to him and certainly no reason why the Cavendish experiment was required. Both claims are unsupported assertions.Nor do you provide any way in which Newton could have justifiably claimed a universal "law".In short you offer no alternative to asserting that Newton used induction, and no reason to suppose that he did not.So what about the question you are still dodging. What is your alternative to induction ?

Without a doubt. I think science was almost purely inductive during its formative years and modern areas of science are founded on these earlier, inductive discoveries.
However I think that science now is more a deductive process.
You can't ever truly get pure-induction or pure-deduction and there is a history of both in the past of science, but I would still say that what’s done today is deductive science, rather than the inductive science of our academic forefathers.In essence we no longer experiment until we find a pattern, we now the deduce a pattern and do experiments to see if our deduction was correct.Science still uses induction and relies on a past foundation of inductive work, but I don't think it's the main tool anymore. The Cosmological constant was always present in his equations, it's impossible to derive them without it. His "mistake" was assuming it had a non-zero value. Essentially because most people have "read science not done science" and still have a Francis Bacon/Benjamin Franklin impression of it.
A bunch of people continuously experimenting to figure something out.
In turn philosophers of science inherit this view and write a philosophy of science based on an old romantic notion of science.This image of science is a far cry from the kind of work done by Feynman, Schwinger, Tomonaga and Dyson in the 60's on QED, as well as other works in modern science.

I note that you agree that science uses induction still and then apparently agree with nwr's assertion that it is myth to say that science uses induction (and nwr means that science has not used made significant use of induction since the time of Newton - perhaps never) It might be an idea to clear that up.

Edit: I see what you meant.I should say that the image of science as purely or largely inductive is a left over from our impression of science from previous centuries and this bears little resemblance to the science of today.I do believe that science still uses and did use induction.This message has been edited by Son Goku, 02-15-2006 06:42 AMThis message has been edited by Son Goku, 02-15-2006 06:43 AM

Oh? You've never read a book on it? You've never opened a math textbook and read Euclid's axioms? Or Russel's? You recreated his entire Principia Mathematica, ex nihilo, starting from a basis of absolutely no training whatsoever?You've never taken notes? Used scratch paper? The thermometer is meaningless - literally, the expansion of the mercury indicates nothing - absent the fact that one degree Farenheight has been assumed to have a certain value.Our units of measure are axioms. Reasoning from those units - taking measurements - is deduction because it's the application of general axioms to specific cases. By definition, deduction. I know of no definition of deduction that requires that it be a process you can do all in your head.

Readers can decide for themselves whether those are different wordings of the same question. In order to get forces from acceleration, you need to know the mass. The mass of the planets and the mass of the sun could only be determined by using Newton's law of gravity. The Cavendish experiment, sometimes described as "weighing the earth" was an important step in determining those masses.There is another interesting point here. If induction had been used to form the inverse square law, then in essence you would have only 6 obvservation - one for each of the planets known at Newton's time. Yet you have been arguing that you cannot do induction with a small number of observations. My claim is that many of our scientific laws are inventions, not descriptions.Scientists are concerned with getting data. But data does not come for free. You need an organized system of concepts in which to express the data, and a system of conventions on how to collect data. My contention is that many scientific laws serve the purpose of introducing these new concepts and presenting the measuring conventions to collect the data that uses these concepts.