That's the whole question.
Per the Stack Exchange -> Philosophy -> Metaphysics Tag Page
Metaphysics is a branch of philosophy concerned with explaining the essence of things, of the fundamental nature of being and the world and the principles that organize the universe. Metaphysics is supposed to answer the question "What is the nature of reality?"
Since it is impossible to answer the question that is not asked... I thought the question best exist, since it "should be answered".
The issue here is not that there is no answer, but that there are many, incompatible answers. This is one of the core questions that tends to define a particular philosophical outlook and commitments. At best, we can give a general survey of some of the major answers:
Not every philosopher considers metaphysical issues, but those that do are certain to have contrasting answers.
The short answer is “42”, see the end of chapter 27 from the book Douglas Adams: The Hitchhiker's Guide to the Galaxy.
The short answer indicates: Just asking for the nature of reality is possibly not the best way to understand the phenomena of our world and to orientate ourself in it.
Metaphysics is an old term, totally overladen with speculations and claims from millenia of philosophy.
In order to change the term into small but valid coin: The best insight into reality is the standard model of cosmology. It spans the frame in the dimensions of space and time. It clarifies that the universe exists the longest time without humans. Hence it is not to expect that anthropocentric approaches provide helpful explanations and suitable models.
The frame of cosmology can be further detailed by other sciences.
From the viewpoint of philosophy it helps to distinguish between ontology and epistemology. The two disciplines deal with the building blocks of the universe, objects and processes (ontology), and with our knowledge and its reliability (epistemology). In addition, for our living together some familiarity with ethics is indispensable.
Metaphysics is supposed to answer the question "What is the nature of reality?"
Reality is by definition all that there is, so nature is part of it presuming it exists, if so then there cannot be a nature of reality.
Maybe what is meant is what sort of thing reality is but once we think of reality as everything which exists, and we admit that we don't know everything which exists, we implicitly accept that we don't know what reality is beyond our definition of it as all that there is.
Understanding a thing seems to consist entirely in explaining it in terms of something else. We explain natural elements in terms of atoms, atoms in terms of protons and electrons etc. However, reality is by our own definition all that there is, so there is nothing outside reality, and therefore nothing we could explain reality with.
"What is the nature of reality?"
In contrast, a saying from Nolan's Westworld: "What is the nature of your reality?"
Asking the question leads us on to 'Know Thyself' which is, arguably, the beginning of a lived life. There is no definitive answer but only the wrestling with the question. Like a Buddhist koan.
"The serious problems of life, however, are never fully solved. If it should for once appear that they are, this is the sign that something has been lost. The meaning and design of a problem seem not to lie in its solution, but in our working at it incessantly. This alone preserves us from stultification and petrifaction.”
--Carl Jung, Modern Man in Search of a Soul, 1933
I would suggest Kant's version of reality; the sum of possibilities. Reason being, for example: when walking around, about to turn a blind corner, I am on the lookout for any speeding cyclist, roller-skater, out-of-control shopping trolley ... basically anything — and that is the reality I have to negotiate; real possibilities that have to be reckoned with. When I have actually turned the corner and find just a couple of pedestrians, well that is the actuality. These definitions make sense to me but perhaps others use different terms. Reality in this sense is actually so much more expansive than actuality. Granted some people call actuality reality.
Heidegger describes Kant's idea of reality in The Basic Problems of Phenomenology, Chapter One: Kant's Thesis: Being Is Not A Real Predicate, page 34
The concept of reality and the real in Kant does not have the meaning most often intended nowadays when we speak of the reality of the external world or of epistemological realism. Reality is not equivalent to actuality, existence, or extantness. It is not identical with existence, although Kant indeed uses the concept "objective reality" identically with existence.
The Kantian meaning of the term "reality" is the one that is appropriate to the literal sense of the word. In one place Kant translates "reality" very fittingly by "thingness," "thing-determinateness." The real is what pertains to the res. When Kant talks about the omnitudo realitatis, the totality of all realities, he means not the whole of all beings actually extant but, just the reverse, the whole of all possible thing-determinations, the whole of all thing-contents or real-contents, essences, possible things. Accordingly, realitas is synonymous with Leibniz' term possibilitas, possibility. Realities are the what-contents of possible things in general without regard to whether or not they are actual, or "real" in our modern sense.
The big picture of reality is stuff spread in space with persisting traits we identify with laws of physics. The stuff seems to be made of a small range of common building blocks which interact in set ways. The interactions tend to have the result of dissipating energy. Very, very, very exceptionally, it seems, conditions allow building blocks to combine in forms we call life, which has happened on Earth. The combined mass of all humans on Earth has been estimated at 450,000,000,000 kilograms, which is about 0.0000000000000000000000000000000000000000001% of the estimated mass of the observable Universe (give or take a few zeroes),which shows how unrepresentative we are of matter generally. As far as we can tell, the stuff of the Universe has been interacting in more-or-less the same way long before human life evolved, and it would continue to interact in more-or-less the same way if all humans died overnight. Of course, there are all kinds of parochial aspects of reality which we take very seriously here on Earth, but we can hardly claim they are part of the big picture.
The nature of reality is The Great Mystery.
The map (what we know about reality) is not the territory (what exists as reality). But some philosophers argue that their map of reality is the territory!
