Is physics based purely on observation?

  • #1
Hello everyone, I recently had a debate with my philosophy teacher about physics, she was saying that physics is purely an observational science, I objected by saying that some areas of physics are based on reasoning and have no observable results to show, stating superstring theory as an example. Am I right? If I am, could you please state some theories based on reasoning and mathematical rigor rather than observation? Thank you in advance.
 

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  • #2
russ_watters
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What does "purely observational" mean?
 
  • #3
sophiecentaur
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On the other hand, Philosophy is not even based on observation - just a set of axioms that may or may not have any relevance to the world - depending on how eloquent the Philosopher happens to be.

Science is all about trying to explain what we observe. Some explanations are more tenuous than others but I think you could say that all explanations / models are developed in the hope that someone, some day, can verify it experimentally. A Scientific Theory can only be such if it is 'disprovable'. Take Higgs Boson, for instance. That was postulated long before an experiment was even thinkable - but there's no point waiting until someone builds measuring gear just in case someone might want to use it for something - you'd be waiting for ever.

So I think your Philosophy teacher was probably right but the word 'purely' seems too much of a quality judgement - reads like "only".
 
  • #4
Nabeshin
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Hello everyone, I recently had a debate with my philosophy teacher about physics, she was saying that physics is purely an observational science, I objected by saying that some areas of physics are based on reasoning and have no observable results to show, stating superstring theory as an example. Am I right? If I am, could you please state some theories based on reasoning and mathematical rigor rather than observation? Thank you in advance.
Your professor is correct. Physics must ultimately submit to experimentation, as that is the ultimate test of any theory. String theory is such a complex theory, we simply haven't worked out any testable predictions of it yet. It is the hope of all the string theorists that eventually we will figure out how to extract predictions from the theory, deciding the question of whether or not it matches up with physical reality. All the work in mathematics and reasoning that has gone into string theory up to the point is in order to get the physical predictions out.

Now, there are mathematicians among us who couldn't care less whether or not string theory is actually a good description of our reality. They're simply interested in the logical structure of the theory of quantum vibrating strings! That's the distinction between physicists and mathematicians though. It's true, the line can seem a little blurry, but even in the most speculative theoretical physics papers, you'll find a short paragraph towards the end describing what things would be like IF the strange theory were true.
 
  • #5
russ_watters
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The reason I asked what "purely" means is that the scientific method has 4 steps and only two of them are about observation.
 
  • #6
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The reason I asked what "purely" means is that the scientific method has 4 steps and only two of them are about observation.
I've heard a lot of ways to divide the scientific method into steps, what are the steps you're talking about?
 
  • #7
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I think your professor is right. Science is (best) defined by a measure of empiricism. Observation is the final arbiter of any and all scientific hypothesis and theories. If you are just sitting and thinking and coming to conclusions based off of some arbitrary system of logic you are not doing science. (you are doing maths or philosophy or something else)
 
  • #9
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Physics may be purely observational. Physicists, not so much. If two theories are put forward to explain a particular phenomena physicists will gravitate toward the one that is more simple and elegant until observational data differentiates one from the other. For example, Newtons theory of gravity was originally disliked because it predicted elliptical orbits instead of the more simple and elegant circular orbits of previous theories.
 
  • #10
sophiecentaur
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I think your professor is right. Science is (best) defined by a measure of empiricism. Observation is the final arbiter of any and all scientific hypothesis and theories. If you are just sitting and thinking and coming to conclusions based off of some arbitrary system of logic you are not doing science. (you are doing maths or philosophy or something else)
Philosophy is a very useful discipline to help in the scientific process because it insists on rigour in making the 'non-experimental steps'. But I have a real problem with the 'self important' stance that Philosophy takes about its own worth. It is 'great fun' to wring out every last aspect of an artificial model of society / religion / culture / the World and it does require a high level of ability. But when Philosophers try to apply their conclusions to the real world, they rely on force of personality and 'marketing skills' to justify applying those conclusions. There always seems to be some step which involves 'faith' where the Scientist makes the same step using 'experiment'.

I guess there are more than one kind of reality and my personal reality is in contention with that of the Philosopher. Hence, 'they' tend to make me cross.
 
  • #11
sophiecentaur
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Physics may be purely observational. Physicists, not so much. If two theories are put forward to explain a particular phenomena physicists will gravitate toward the one that is more simple and elegant until observational data differentiates one from the other. For example, Newtons theory of gravity was originally disliked because it predicted elliptical orbits instead of the more simple and elegant circular orbits of previous theories.
Our posts crossed there.
I should say that the rigour which is required in 'good' Philosophy should be applied when Scientists start to make arbitrary choices of model. The reductionist principle is pretty universal in Science and it can be justified (in the absence of experimental evidence in a particular case) on the grounds of experience (which is experimental in nature). Even Scientists (who are mostly human, after all) have emotional attachments to certain methods. Conservatism, for instance, is a very health influence of mainstream Science. Without it, we'd be on a random walk. Any worthwhile hypotheses will eventually find its way into general acceptance as a theory despite the influence of prima donna experts.
 
  • #12
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I like this video:

https://www.youtube.com/watch?v=EYPapE-3FRw
 
  • #13
As I understand it, modern physics is decades ahead of any experiments possible with todays technology..
To that extent I'd say it's moving away from being purely obeservational

However, it's roots are still solidly in observationalism, if that's the word you'd use.
 
  • #14
Pythagorean
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I think feynman's scientific method is more accurate than the 4-step method; but still, not everybody does things in that order. Some people play first with their system and then hypothesize after they know their system. Or formulate the hypothesis as they write their paper (already knowing the system and what's novel having to make a story out of it).

ie, the hypothesis can just as easily be the last step.
 
  • #15
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Hello everyone, I recently had a debate with my philosophy teacher about physics, she was saying that physics is purely an observational science, I objected by saying that some areas of physics are based on reasoning and have no observable results to show, stating superstring theory as an example. Am I right? If I am, could you please state some theories based on reasoning and mathematical rigor rather than observation? Thank you in advance.
You could just as easily argue that everything is based on observation, but physics is a science which means it deals with systematically cataloging and organizing data including such unobservable possibles as the Many World's theory. The only additional restriction with physics is that it must relate to fundamental physical properties.
 
  • #16
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Physics may be purely observational. Physicists, not so much. If two theories are put forward to explain a particular phenomena physicists will gravitate toward the one that is more simple and elegant until observational data differentiates one from the other. For example, Newtons theory of gravity was originally disliked because it predicted elliptical orbits instead of the more simple and elegant circular orbits of previous theories.
mrspeedybob, the observation of elliptical orbits preceded Newton. Tycho Brahe collected huge amounts of data on the orbit of mars by observation and passed that data down to Kepler, who spent years trying to make sense of it. Kepler was the first to realize the collected observations had to add up to an elliptical orbit, and he proposed that all orbits were elliptical.

In astronomy, Kepler's laws give a description of the motion of planets around the Sun.
Kepler's laws are:

1.)The orbit of every planet is an ellipse with the Sun at one of the two foci.

2.)A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.

3.)The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
http://en.wikipedia.org/wiki/Kepler's_laws_of_planetary_motion

This was old news by Newton's time. Newton's theory was actually liked because it explained how universal gravitation ought to result in elliptical orbits thereby complying with Kepler's laws and simultaneously explaining that the familiar force of gravity was behind it.

anthonych414 said:
Hello everyone, I recently had a debate with my philosophy teacher about physics, she was saying that physics is purely an observational science, I objected by saying that some areas of physics are based on reasoning and have no observable results to show, stating superstring theory as an example. Am I right? If I am, could you please state some theories based on reasoning and mathematical rigor rather than observation? Thank you in advance.
With Newton specifically in mind, I think your teacher has no case. The Principia is about 2% observation and 98% reasoning to make sense of the observations. As you probably know, Newton coherently assembled all known physical laws for the first time, and bent classical geometry in strange ways to serve the purposes of calculus, in order to lay out his case for universal gravitation. Newton was prompted to explore the issue because of the observations, but he's certainly not merely describing things: he's rigorously reasoning things out mathematically. I think this is eminently typical: observations are often inexplicable, and physics seeks to rigorously reason out the explanation.
 
  • #17
sophiecentaur
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I have great difficulty taking a lot of, even high powered, philosophy seriously. Every conclusion in a philosophical argument must start with an implicit or explicit "IF . . . .".
In Science / Physics, conclusions have a much 'harder' input requirement - i.e. "This model explains the following observation. . . ".

I remember listening to an interview with a prestigious Christian Philosopher about why one should believe in God. Her clinching (?!) remark was "If you are optimistic then you MUST believe in God". Now, there's a 'bootstraps' argument if ever I heard one.
 
  • #18
Pythagorean
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Empiricism is a philosophy... IMO, THE most high powered philosophy.
 
  • #19
sophiecentaur
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And is it not the same as Science?
 
  • #20
Pythagorean
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No. It's the most likely philosophy a scientist would have, especially in the west. But science is a combination of philosophy and mathematics.

Everyone has philosophical baggage though, when you start actually detailing their interpretations of the data. "empiricism" is a very broad, vague word: our miniature philosophies can be the most dangerous or enabling.
 
  • #21
Chi Meson
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I have great difficulty taking a lot of, even high powered, philosophy seriously. Every conclusion in a philosophical argument must start with an implicit or explicit "IF . . . .".
Oh man, do I ever agree with you. Having had the opportunity of taking several philosophy classes, including a "great" class on Hegel taught by a renowned professor; and after many arguments with sophomoric philosophizing students and finding them the same as arguments from PhD's, mostly pointing out how everything is "just a theory" ... gah!

There is more data/evidence of massive planets orbiting distant stars then there is of most philosophy arguments.
 
  • #22
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Hello everyone, I recently had a debate with my philosophy teacher about physics, she was saying that physics is purely an observational science, I objected by saying that some areas of physics are based on reasoning and have no observable results to show, stating superstring theory as an example. Am I right? If I am, could you please state some theories based on reasoning and mathematical rigor rather than observation? Thank you in advance.
I think that you're more correct than your philosophy teacher.

Saying that physics is an observational science is sort of redundant. All sciences involve observation. In fact, observation is the final arbiter wrt competing theories/hypotheses.

Saying that physics is purely an observational science is a curious statement. Physics involves the formulation of hypotheses/theories, and the testing of those hypotheses/theories. The formulation of the hypotheses/theories is philosophy. The empirical testing is science.

And then there's the interpretation of the empirical results, and the interpretation of the mathematical formalisms -- both of which are philosophy, not science.

Superstring theory isn't yet science, it's philosophy. When it generates some testable, falsifiable hypotheses, then it will be science.

Simply stated, theoretical physics is philosphy, experimental physics is science. But both of these taken together constitute the science of physics. They go hand in hand. I don't see how there could be one without the other.
 
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