What are some specific examples of metaphysical issues?
In the previous post I argued that the task of ontology is to answer the question: “What kinds of entities are real?” What does that really mean?
I. There is the proto-ontological issue of the nature of being an entity. Since doing ontology without first answering the proto-ontological question is logically backwards, it’s surprising that many major philosophers have little to say about what an entity is. [I state my view in the post “Define Reality.”]
There are related issues concerning, for example, essence and predication. With respect to essence, is there an important distinction between essence (whatness) and existence (thusness)? How should they be understood and what is the relation between them? With respect to predication, there are issues concerning language and ontological analysis (such as ‘Are there ontological simples?’).
II. The following are some traditional metaphysical issues.
A. Perhaps the paradigmatic metaphysical issue concerns how best to understand the nature of qualities. As I mention in the post “Define Qualities,” if there were no qualities there would be no intelligibility. In other words, a world requires qualities.
That explains why nearly all the great philosophers have either an explicit or implicit position on the nature of qualities. Unfortunately, they don’t all use the same terminology and sometimes the issue concerning how best to understand generality is confused with the issue of how best to understand the nature of qualities, but it is almost always possible to figure out which of the three alternatives a major philosopher holds. [I argue for, but don’t defend, my answer in that post on qualities.]
B. What is it to be an individual (particular)? Specifically, are individuals substances or not? This is an important metaphysical issue for self understanding.
If they are, what are substrata? Are they momentary or continuant? Is there one substance or two substances or many substances?
If they are not, how are an individual’s qualities clustered together? How are individuals individuated without substrata?
[Although I do not defend my position by answering objections there, I give my answer in the post “Substance.”]
C. Assuming that numbers are not the same as numerals (because they are what numerals denote), are numbers real? For example, do negative numbers, imaginary numbers, and infinite numbers exist?
Pythagoras thought so. For him, this wasn’t merely a question in the philosophy of mathematics; it was about everything in the world. His ultimate explanation went beyond standard ones about body [matter] to form, specifically, to the idea that reality can be understood as numbers.
D. Is anything divine real? In other words, do gods exist or does a god exist?
Answering this intelligibly first requires defining what is under discussion, and that proves to be very difficult, which may not be very surprising in the sense that you are trying to use natural categories to understand a supposedly supernatural subject matter. In practice, there is a lot of philosophy to be learned by seriously examining this question.
E. What is mind (consciousness)? Are all entities somehow mind? If some entities are not mind, what is the relation between mind and those entities?
F. What is body? Are all entities somehow body? The concept of matter has radically evolved over the millennia.
G. What is the role of logic? Is it somehow due to us or is reality itself somehow logical?
This list of metaphysical issues could be extended and is meant to be representative and not exhaustive. However, it is sufficient to provide a clearer idea about the kinds of topics addressed by ontologists.
Perhaps the most important issue is about metaphysical issues themselves. Is it possible to solve them conceptually? [See the posts “Define Understanding” and “Epistemology.”]
Discursive (conceptual, discriminatory, divisive) reason is dualistic. If reality is unitary, it is impossible for discursive reason to apprehend it.
For example, Zengcan, the third patriarch of Chinese Zen [Chan], wrote “Affirming Faith in Mind,” which is considered to be the oldest extant Chan document. In it, he argues, “When you assert that things are real, you miss their true reality / But to assert that things are void, also misses reality.” [Rochester Zen Center translation.] Reality cannot be adequately grasped conceptually.
His criticism is quite clear: “Remaining in duality, you’ll never know of unity . . . Thought cannot reach this state of truth.”
His prescription is also clear: living well, living without being misled, requires us to “Cut off all useless thoughts and words.”
Notice that he is not recommended that we somehow stop conceptualizing, which is impossible. What he is recommending is that we stop all useless conceptualizing.
Are criticisms like Zengcan’s (and Kant’s) correct?
The only way to tell is to follow his prescription and determine for yourself whether or not it cures “the mind’s disease” of incessant conceptualizing that actually prevents us from apprehending what is ultimately real and “beyond both emptiness as well as form.”