'Metaphysics' is one of those words whose denotation can vary with circumstances.

It comes originally from tà metà tà fusiká ('the "after the Physics"'), the title of Aristotle's work on ontology, and then meant 'ontology'. 

By the 16th century, English usage had extended the term so that it also meant 'the study of things that transcend nature' - that is, the supernatural.

Of course you're entitled to your preferences, but I don't think you can now insist that it only has one of those meanings.

I believe that the supernatural and the natural share this reality and that the necessary principles are common to both

Then demonstrate the existence in reality of the supernatural and we can all take it from there.

TransJ

define natural reality as more or less the particular nature of existence

The ‘universe’ / ‘reality’ is the totality of all the phenomena that are out there, including those we’re yet to discover - the realm of the physical sciences.  Can we agree on that?

and the supernatural as more or less the universal nature of existence.

I don’t understand this part.  We have the universe.  The manner in which it exists is contained within it (ie is in the realm of the physical sciences).

What else do you say there is?

TransJ

one reality/ universe that is a synthesis of the natural and supernatural or physical and metaphysical or the particular and universal.

Reality, you say, is made up of two categories of phenomena - the realm of the physical sciences (no argument there) and another one which you variously call 'supernatural' and 'universal'.

If you're using 'universal' in the Kantian sense, I don't hold with it.

The particular and universal are both objective parts of our universe.

Therefore you can point out to me something with objective existence that's supernatural.  Please do so - it will clarify a great deal.

Say the universe contains the (universal)  possibility of form and in the universe we find particular forms : car, worlds, galaxies and so on.

Do you mean 'form' here as Plato meant 'form'?  I regard that notion of forms as untenable, on grounds of logic, evidence and categorization.

 Blu:Reality, you say, is made up of two categories of phenomena - the realm of the physical sciences (no argument there) and another one which you variously call 'supernatural' and 'universal'.

TransJ:Yes, reality is made up of two categories of reciprocal phenomena. A particular and universal synthesis. 

Blu:If you're using 'universal' in the Kantian sense, I don't hold with it.

TransJ:Tempting but the “absolute allness of the appertaining parts” does not seem to work well with  reciprocal universals. 

Blu:Therefore you can point out to me something with objective existence that's supernatural.  Please do so - it will clarify a great deal.

TransJ:Because we are talking about things within the universe, supernatural  or metaphysical would mean in a since things normal beyond our ability to experience.  You defined the universe in some what metaphysical terms as “the totality of all the phenomena that are out there, including those we’re yet to discover “. You or I have not nor can experience the totality of all phenomena of the universe. It would be a supernatural act for a human being as they now exist to do so. In that since the  universe as a totality of all phenomena is a supernatural objectively existing thing to our natural experiences. 

Blu:Do you mean 'form' here as Plato meant 'form'?  I regard that notion of forms as untenable, on grounds of logic, evidence and categorization.

TransJ: No, but I like to get as close to that idea as possible. My thinking is that Form identifies  a universal or uniform possibility or potential of the totality of all phenomena ( the universe). However keep in mind that metaphysics for me is about first principles or the necessary categories for reality to exist, the supernatural is not its main focus.  

TransJ

reality is made up of two categories of reciprocal phenomena. A particular and universal synthesis.

Still not clear about this universal word.  Give a nice clear example that shows what you mean by ‘universal’ in this sense.

Because we are talking about things within the universe, supernatural  or metaphysical would mean in a since things normal beyond our ability to experience.

So by definition no examinable evidence supports your earlier assertion that these ‘supernatural’ things have objective existence.

On what basis, if not evidence, should we think they exist at all?

the  universe as a totality of all phenomena is a supernatural objectively existing thing to our natural experiences.

That’s a complete non-sequitur as you’ve presented it.  Phenomena may well exist that a human can’t experience - the instantaneous formation and self-annihiliation of particle / anti-particle pairs as in the Casimir effect, for example - but that's part of physics, not ‘supernatural’.

Give an example of a supernatural phenomenon and say what quality identifies it as supernatural.  And especially, what quality distinguishes it from the imaginary.

Form identifies  a universal or uniform possibility or potential of the totality of all phenomena ( the universe).

I don’t follow that at all.  An example of a ‘form’ as you intend the word, please.