Sir Isaac spoke, and there were light. But why, really?

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    Light sir
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Discussion Overview

The discussion revolves around the principles of motion as articulated by Newton, particularly the idea that a body in uniform motion remains in that state unless acted upon by an external force. Participants explore the philosophical and scientific implications of these principles, questioning the underlying reasons for the existence of forces and the nature of motion. The conversation touches on historical perspectives, the evolution of thought from pre-Newtonian ideas to modern interpretations, and the relationship between motion and reference frames.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested
  • Historical

Main Points Raised

  • Some participants assert that Newton's laws are accepted as a fundamental description of motion, but question the deeper reasons behind why these laws hold true.
  • Others propose that the relationship between action and cause is intrinsic, suggesting that without a force, there can be no movement.
  • One participant highlights the historical context, noting that pre-Newtonian physicists had a different understanding of motion, believing that objects naturally remain at rest until acted upon by a force.
  • A later reply discusses how Einstein's theory of relativity complicates the understanding of motion, indicating that motion can be relative depending on the observer's frame of reference.
  • Some participants express skepticism about the ability to fully explain the existence of forces, suggesting that it may be a philosophical question rather than a purely scientific one.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the reasons behind the principles of motion. There are multiple competing views regarding the nature of forces and motion, with some advocating for a philosophical perspective while others focus on scientific interpretations.

Contextual Notes

The discussion reflects a range of assumptions about the nature of forces and motion, with some participants relying on historical definitions and others considering modern physics. There are unresolved questions about the implications of relativity and the philosophical underpinnings of motion.

salamander
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Some vise guy once stated that "a body in uniform motion stays in uniform motion, if no force is acting on it, a body at rest stays at rest if no force is acting on it."

Sure, our universe works this way, I think we all agree on that... but why does it work like this? Does anyone know?

As far as I know, not relativity nor quantum mechanics or string theory violate this principe (allthough I know little of relativity and extremely little of quantum mechanics and string theory). Is that correct?

Cheers fellows.
 
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How could it not work like that? I think of it as part fact, part definition. If there is an action then there MUSt be a cause. No cause (force) no action (movement)
 
yes but we explain staying stuck to the ground with gravity whereas u just thought of it as fact a few centuries ago. For full definition of our srroundings we need to question why. But it seems beyond everyone to explain why forces are.
 
Oh, so this is philosophy, well perhaps then...

Should we simply negate the reason to have forces simply because we can not imagine a world without them?
 
Newton's laws of motion are over-simplifications of a more subtle situation described by Einstein. In Relativity, motion and the lack of motion just depend upon your point of view. That is why a body in motion seems to maintain it's velocity and direction unless something else changes it, because for all we know it is we who are moving rather than the object we are observing.
 
ok. thanks.
 
Yer welcome.
 
How could it not work like that? I think of it as part fact, part definition. If there is an action then there MUSt be a cause. No cause (force) no action (movement)

This is precisely what pre-Newtonian physicists said. They believed essentially the same thing as Newton except had it reversed, and as we all know they were wrong. They thought that the natural position of an object was at "rest" until a force acted upon it. This seems completely in line with common sense (and in fact with what you stated in your post). You throw a rock, your force (cause) guides it through the air but it always inevitably attempts to come back to its natural state, which is resting on the ground. Newton suggested the opposite, you throw a rock, it will continue indefinitely in motion unless another force acts upon it. Essentially Newton was able to transcend Earthly experience and think outside the box. Newton's laws of motion, though they seem fairly simple to us moderns, were actually extremely counter-intuitive.

My point in all of this is that Newton's laws aren't as obvious as you seem to imply. The "obvious" would end up being the opposite of what Newton discovered. The key in all of this, of course, is gravity which wasn't really viewed as a force until Newton.
 

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