You can't discover or prove things which are not observable.
If there are such things, you can only know them if they are taught to you by someone you find credible.
There are many who claim to have been eye-witnesses to such teaching.
Like any juror, you have to decide whether you find such eye-witnesses credible.
I have never seen a strange quark.
I have no capability to observe one.
I have to decide whether the group of physicists who say they have observed them are credible.
Stan, I used to think like this. Treating science more like an appeal to authority (Top scientists say X is true, therefore it is true), rather than the process by evidence can be gathered for or against a hypothesis.
In that mindset, religion is the ultimate appeal to authority and it feels 'stronger' than science. That is, top religious people say X is true with ABSOLUTE certainty! But scientists cannot absolutely prove something, they only claim that X is very, very likely. Religion is stronger, and science is very useful, but ultimately cannot answer many questions.
There is reality out there. The universe, and whatever greater reality lies beyond it, are real. This is the 'territory'.
There is also our mental belief about what is real. Our belief, our mental model of the world, is the 'map'. Our belief can be correct or incorrect. The map can accurately reflect the territory, or it can fail to match it.
http://wiki.lesswrong.com/wiki/The_map_is_not_the_territoryThrough empiricism (observation - in a wider sense than just 'seeing with our eyes'), we can gather evidence about whether our mental map matches the territory of reality, or not.
http://lesswrong.com/lw/jl/what_is_evidence/http://lesswrong.com/lw/jn/how_much_evidence_does_it_take/So in the case of the top quark, we cannot see it with our eyes. Our standard method of updating our mental map to match the territory of reality doesnt work. When our shoelaces were untied, we learned this because photons from the sun bounced off our untied shoelaces, into our eyes, and our brain processed that information. It then updated its belief that our shoes were tied (with very high probability), to our shoes being untied (with very high probability).
We cannot do that with Top Quarks, but that does not mean we cannot gather evidence about whether or not there is a thing in reality which has the properties we describe with the term "Top quark".
Building upon our previous understandings, physicists constructed a model of the universe, a hypothesis, which could be true or false. The model predicted top quarks, and predicted they would have certain properties. The model predicted that if it was true, when we smashed certain particles together in an accelerator at high energies, we would sometimes see top quarks be generated. It predicted what percentage of the time and under what circumstances they would appear.
We tested this, building the accelerator and using it. We found that to high precision, the prediction of top quarks (our map) matched the reality of what we observed (the territory). While it would not be possible to gain ABSOLUTE certainty of this, the probability that it was true became very very high.
(You never get absolute certainty or uncertainty in something, because 0 and 1 are not probabilities!)
http://lesswrong.com/lw/mp/0_and_1_are_not_probabilities/More recently, we did this process again with the Higgs Boson. The following book by Physicist Sean Carroll does a fantastic job of describing the theory behind, and process of discovering evidence for the higgs boson, how much evidence we gathered, etc:
http://www.amazon.com/Particle-End-Universe-Higgs-Boson/dp/0142180300/ref=sr_1_1?ie=UTF8&qid=1422480417&sr=8-1&keywords=the+particle+at+the+end+of+the+universeWith the scientific method, we become the lens that sees its flaws. We can recognize that our mental map is not guaranteed to match the territory of reality. We can figure out what beliefs are correct or are wrong, and modify them.
http://lesswrong.com/lw/jm/the_lens_that_sees_its_flaws/We know that we might just be a brain in a jar, and a demon is feeding us inputs that correspond to the world we see (
http://en.wikipedia.org/wiki/Maxwell%27s_demon). We also know that the universe might operate on mathematical laws, the fabric of real things (
http://lesswrong.com/lw/eva/the_fabric_of_real_things/)
While we cannot say for CERTAIN that we are in one and not the other, one of these scenarios is massively more complex than the other. A reality which operates on a certain number of mathematical laws which govern what is real and what is not, can be specified in some number of bits of information. On the other hand, a demon simulating the entire universe and all inputs and outputs we see, requires an enormous number of bits of information in order to specify it.
This allows us to compare the probability of each of these being true by Occam's Razor:
http://lesswrong.com/lw/jp/occams_razor/In the end, through the scientific method, we can know things. We cannot know with absolute certainty (100% is not a real probability). But we can know with a high probability.
We do not need to rely on appeals to authority. Appeals to authority are only as accurate as the mental map of the authority you have chosen to follow. But what matters in terms of something really being true, is whether that map matches the territory of reality.
Returning to the earlier question of whether there is morality is subjective:
While morality is not specified in the laws of nature that govern whether something is real or not, neither are most of the complex things which with we interact with in our lives. Neither is the idea of what 'life' is.
As particle physics is built upon whatever underlies it, and chemistry is build upon that, and biology is build upon that, and consciousness is build upon that, leading to what it means to be a human being, so can morality also come about.
We can empirically study societies of sentient beings which we refer to as humans, and determine certain ways in which their collective benefit could be maximized. These things can be 'morality'.
Amazingly complex things can come from things that seem simple.
The mandlebrot set comes form the equation Z(n+1) = Z(n)^2 + C.
http://en.wikipedia.org/wiki/Mandelbrot_setIt is fascinating in its complexity.
So can morality, free will, life, consciousness, biology, chemistry, physics, etc, derive from laws of nature that we are approaching a good understanding of but do not yet fully know.
Steven Pinker would say that morality "is out there" and can be determined empirically, and I would agree:
http://en.wikipedia.org/wiki/Steven_Pinkerhttp://en.wikipedia.org/wiki/The_Better_Angels_of_Our_NatureI doubt anyone has actually made it to the end of my ramblings, but if you have, wow, you probably think I'm nuts. Or maybe not.