0.) Visualize each true proposition P as having its own location. Make God write a book of all P’s, or have him write each one on a card, put it on a stake, and pound it into the ground.
1.) Either we know some P is irrefutable or not. If so, we have run over all possible locations for a true ~P and found none. If not then, for all we know, among all possible locations for a true ~P there might actually be one.
2.) It follows that we know all possible locations for any proposition, though we disagree over the way in which we know them. Maybe we know them only as a great “out there” beyond our knowledge (like the infinite ocean beyond a slowly growing island of knowns, or like the task of distinguishing green emeralds from grue ones). Maybe we know them sufficiently to know that some ~P’s cannot be found, as certainly seems to be the case with certain logical axioms or with any sufficiently general or very concrete P like “Something exists” or “I exist” or (I’m checking) “At the moment I have two hands”.
More likely, some claims are refutable and others aren’t, but we know all possible locations either way. Let the state of being a P location be called being.
3.) Being in this sense is the truth of propositions. This includes negative claims, claims about fictional characters, compound claims made of impossibles (if wishes were horses then beggars would ride), some claims made with alienans modifiers (Socrates is dead, my car can’t drive)…
4.) We’re using propositions only as a way of getting to the metaphysics, so replace P with whatever its ontological equivalent is. I assume we all know what this is for “I exist” or “at the moment I have two hands”, and I assume we’ll have to work out some differences about “Don Quixote dies in his home village” or “Pluto is not a planet” or “There are no weasels in my shirt”. But how do we get from being as truth being ontologically?
5.) Being in an ontological sense is also being as true, and so is intelligible. While both accidents and substances are beings, accidents have less intelligibility than substances, since the accident strictly both includes its proper substance and is said of it. As a result, if only noses are snub, then speaking of a snub nose is either to say the same thing twice or to fall into the infinite regress of snub nose = snub-nose nose = snub-nose-nose nose… Thus, being in an ontological sense will first be substances as opposed to accidents.
6.) Intelligibility both shows that substance is more a being than an accident and that the causes of substances are more being than substance itself. If you ask why something a ship you explain why it has the properties it has and is used for that reason, both of which are causes of the ship.
While the matter out of which something is made is a cause it is clearly less of a cause than the form, agent, or goal.
To conclude: because being in an ontological sense is intelligible, it is least of all true of accidents, more true of substances, and most of all true of causes of substances; among causes, it is less true of matter than of the other causes, even though it is often the case that the matter is the first thing we can understand. So even while we learn more about life by knowing it is carbon-based or cellular this description is subordinate to other orders of causality. Knowledge moves slowly though, so it can take a very long time even to get a clear view of matter.