What is a theory and how does it relate to the universe?

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In summary, a theory is a model of the universe that is based on observations and mathematical equations. If observations do not match the predictions of a theory, then the theory can be disproven.
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rudransh verma
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I was reading brief history of time by hawking and there I stuck on this line “A theory is a model of universe or a restricted part of it and a set of rules that relate quantities in the model to observations we make.” What is it saying? Please elaborate. What are rules and quantities ? Also “You can disprove a theory by finding even a single observation that disagree with the predictions of the theory.” What is this prediction ?
 
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Think of Newton's theory of gravitation. Now explain it to me in Hawking's terms: restrictions ,quantities, observations.
 
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rudransh verma said:
I was reading brief history of time by hawking and there I stuck on this line “A theory is a model of universe or a restricted part of it and a set of rules that relate quantities in the model to observations we make.” What is it saying? Please elaborate. What are rules and quantities ? Also “You can disprove a theory by finding even a single observation that disagree with the predictions of the theory.” What is this prediction ?
The label we put on something is not very important. Whether we call it Newton's Theory of Gravity, Newton's Law of Gravity or the Newtonian model of Gravity doesn't matter. It's still ##F=\frac{Gm_1m_2}{r^2}## and ##F=ma## regardless.

This theory of gravity predicts that in the absence of other effects all objects fall at the same rate. So one prediction of the theory is that if we set up a bell jar with a vacuum and if we arrange to drop a feather and a lead ball in the jar at the same time, they should hit the bottom at the same time. If we perform this experiment and observe that the two do not land at the same time, that would contradict the theory of gravity.

Of course, one would want to look carefully for confounding factors before accepting an experimental result which is so starkly in conflict with this particular theory. See this Wiki article (the OPERA faster-than-light neutrinos) for a real-life experiment in which confounding factors existed.
 
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rudransh verma said:
I was reading brief history of time by hawking and there I stuck on this line “A theory is a model of universe or a restricted part of it and a set of rules that relate quantities in the model to observations we make.” What is it saying? Please elaborate. What are rules and quantities ? Also “You can disprove a theory by finding even a single observation that disagree with the predictions of the theory.” What is this prediction ?
An observation is a measurement of a quantity.
Rules are mathematical equations with those quantities as variables, e.g. their behavior with respect to the quantity time.
All rules (equations) which contain a certain given set of observations (measurement and variables) build a theory.

If we define theory top-down, and not bottom-up what I just did, then we consider a part of the universe, collect all related quantities, measure them (or try to), and find equations among them (or try to).

In the end, we have a mathematical framework, that describes the part of the universe we started with as a model. The translation process between observations and equations is an interpretation of that model.

Theory is primarily only a word. I attempted to describe it by its normal use. A philosopher would write a book about what I just put in a few lines. I would add that Sir Charles Popper did, however, I do not really want to recommend that book.
 
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1) What is a theory?

A theory is a well-supported and widely accepted explanation for a set of observations or phenomena. It is based on evidence and can be used to make predictions about future observations.

2) How does a theory differ from a hypothesis?

A hypothesis is an educated guess or prediction about a phenomenon, while a theory is a well-established explanation that has been extensively tested and supported by evidence. A hypothesis can develop into a theory if it is repeatedly tested and validated.

3) How do theories help us understand the universe?

Theories provide a framework for understanding and organizing the vast amount of information and observations we have about the universe. They allow us to make sense of complex phenomena and make predictions about future events or discoveries.

4) Are theories always accurate?

Theories are the best explanations we have based on current evidence, but they are not infallible. As new evidence is discovered, theories may be revised or even replaced by more comprehensive explanations. However, this does not diminish the value and usefulness of existing theories in understanding the universe.

5) How does the scientific method relate to the development of theories?

The scientific method is a systematic approach to investigating and understanding the natural world. Theories are developed through this process of observation, experimentation, and analysis of data. They are continually tested and refined, demonstrating the effectiveness of the scientific method in advancing our understanding of the universe.

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