[flagged]
One example of something that is not falsifiable is a deductive argument. Deduction isn't science; it is logic. A deductive argument is true regardless of the truth values of its constituent propositions. So in the most literal sense of the world, a deductive argument is not falsifiable.
Another example of non-falsifiability is verbal bunk that refers to poorly defined or undefined concepts. The claims are not specific enough that they can be investigated and found true or false.
E.g. "The world didn't exist yesterday; it came into being moments ago, with everything in it, including all your memories, and all of civilization and its apparent historic record." Okay, great; by what means of investigation can you tell that this is right? If this claim were false, how would the investigation inform you?
Claims about gravity are falsifiable if they are specific and testable. E.g. "If I release this rock, it will move toward the ground and come to rest" is falsifiable because in some imaginary world, it could happen that the rock instead flies up and away when released. The claim is specific: we can construe what kinds of events could be observed which would make it false, like that the opposite of what is predicted happens. If a proposition is falsifiable, and we are not able to find it false, then that gives us confidence that it may be right.
Falsiblity is not the defining concept of science method. There are quite a few schools on that.
Suppose we have not done any scientific investigation at all yet, and just have a hypothesis about something. That hypothesis should be a falsifiable statement, otherwise it is not something that can be investigated (e.g. by a scientific method). It doesn't define the method, but it defines the characteristics of some of the inputs and outputs.
Popper was one of those people. He was not a scientist. He never had anything to do with science. He was a sophist. He talked rings around people in such a way that they never knew what the hell he was talking about, but they assumed it must be profound and amazing.
Karl Popper himself based his ideas about science not on actual science, but on the philosophies including Marxism and Freudian psychology.
Karl Popper's own words: "A theory which is NOT REFUTABLE by any conceivable event is non-scientific." Therefore the theory of gravity is not a scientific theory because nobody has yet conceived of an event or experiment which refutes it.
I realise this will cause a negative reflex among those who are addicted to internerding and have held tightly to the unfounded belief (picked up from other internerds) that "Science must be falsifiable!", but it's just not reality. It's just a little thing that people saw on Wikipedia, latched on to, and figured it was really significant and legitimate. But it's just Popper's nonsense.
There are plenty of extensive criticisms of Popper's sophistry out there by actual scientists and philosophers. Feel free to read some.
As for the scientific method, if you can't do a web search and find out what they actually is, well, nobody can help you.
A True Scotsman's power web search, not just any old search that lands on some little thing in the Wikipedia or its ilk.
I think you're misunderstanding it?
The requirement isn't that there exists an experiment that proves gravity wrong, and has been performed in reality. The requirement is that for the theory you propose, there must be some conceivable scenario in which you decide your theory is incorrect.
Eg, if you posit "All swans are white", when it's falsifiable. All you need is a black swan to show up. But there is no requirement for this to actually happen, there's no problem with every swan in the universe being white.
Also associated are several ideas of science being value neutral and observations being theory agnostic which were foundational to these view points have been seriously challenged.
There's no scientific way around underdetermination, but there certainly are a number of philosophical ways around it.
Starting with: I'll believe whatever the heck I want to believe.
Your assessment is very harsh. Popper's framework is hugely influential in science.
As a small quibble, there is no such distinction between "laws" and "theories". In common language a theory may imply less certainty than a law, but in science this is not the case.
[Yes i am aware that atoms don't necessarily conflict with waves]
Law: A simple relation of limited scope intended to describe a single phenomenon, for example Ohm's Law.
Theory: A description or narrative of how and why, which may include laws, data, observations, etc.
There is according to the academic circles I participated in, although it wouldn't surprise me if most physicists you meet wouldn't know that.
I don't think the principle has anything to do with the difficulty or hardness of falsification. If a theory excludes something from occurring in reality, it is falsifiable, if it does not, then it is not falsifiable.
So think about it like this, if a theory is "compatible" with everything that happens, it really does not make any predictions, as regardless of what happens, the theory holds. What the point of such a theory is is unclear.
General relativity precludes many things from happening, and many tests have been performed that would have detected things that general relativity precludes from occurring: https://en.wikipedia.org/wiki/Tests_of_general_relativity
Yes, I agree, but like I said it's much harder to find what these are and create experiments to show them. I'm also saying the theory part is more than the math formula, it's the explanation.
Theories are the explanatory part to explain why a law or correlation occurs. The law can be falsified, but I think you're right, that it's very hard to falsify the theory portion.
You falsify the predictions of a theory.
When a new theory works better and explains/predicts more the old theory is said to be falsified.
Einstein's theory of general relativity falsified Newton's law of universal gravitation.
If you want to take this even further (which is a leap that would certainly upset most people's sensibilities) - Einstein proved that gravity doesn't exist. What does exist is the curvature of spacetime which explains all the phenomena which we used to attribute to gravity.
Einstein falsified gravity.