The Problem
Metaphysics studies reality at the most fundamental level, whereas science explores reality only in specific ways. For example, physics studies things insofar as they move, biology studies things insofar as they are alive, and chemistry studies things insofar as they are composed of microscopic parts; but metaphysics studies things insofar as they are real. It seems like metaphysics should hold a place of eminence amongst these studies, yet science is constantly discovering new and interesting entities (= existing things), whereas metaphysics isn’t. How can metaphysics claim a place of eminence when it can’t produce results like science? And, can metaphysics discover anything that exists?
Here’s an argument that shows this difficulty for metaphysics:
A1: discovery of new entities
1. Some disciplines discover new and strange things that exist
2. This is a very important achievement that shows their worth
3. Metaphysics doesn’t discover any new existing things
4. So, metaphysics does not have the same worth
Response
An obvious response is that this argument has an undistributed middle. Discovery of new entities may show a discipline is important, but this doesn’t mean it is the only arbiter of worth. For example, metaphysics has something to say about the way these entities exist. While it was the achievement of science to discover quanta and their strange behavior, it falls to metaphysics to determine which amongst several options are true about them. Is the world just a collection of quanta? Are macro-level objects just as real as the quanta that make them up? Is it the case that quanta exist only virtually once they are part of a larger thing? Getting the right answer here can’t be a matter of empirical investigation because there is no possible discernible difference between these three options. Instead, it is a matter of the rigorous reasoning of metaphysics.
We still might wonder at this disparity in discoveries, though. Why is it that metaphysics can’t find anything new? The explanation is two-fold. First, metaphysics deals mostly in necessity: given certain facts about existing things, what must they exist like? However, there are unfathomably-many possibilities of what could exist. The fact that these are possible–but not necessary–objects means that we must use our senses to find out which possibilities are actual. We can’t reason to the existence of contingent things unless we are given some facts that necessitate their existence. So, it makes sense that science, relying on empirical tools that reach the contingent, would discover their existence whereas metaphysics wouldn’t.
Second, metaphysics is mostly interested in things insofar as they exist. This means the results of most metaphysics apply to all real things–or, since things that don’t exist are nothing, we could simplify this to say they apply to all things. While our souls may be very different from our soles, the lessons of metaphysics will often times apply equally to both. Thus, metaphysics will not often be in the business of making distinctions between kinds of real things in the first place, let alone of discovering new distinctions.
However, that isn’t to say it never discovers any new entities. As I said, metaphysics claims that given certain parameters, things must exist like such-and-such. What if we, through some other discipline, find some parameters that necessitate the existence of something new? This would count for the discovery of a new entity by metaphysics. For example, some metaphysicians think that, given the existence of repeatables like properties, kinds, and relations, there must exist some real entity, universals, that explains the repeatability.
Actually, they wouldn’t even have to say the existence of real universals is necessary. They could use abductive logic to show the existence of universals best explains these repeatables. For more on how that’s possible, see here: https://youtu.be/-APA1cJYkwM. Either way, it seems possible that metaphysicians discover at least some entities.
virtue. This can easily be mistaken for an attack on the existence of virtue itself, but I think Socrates’ purpose is to bring Meno to a better understanding of virtue because he believes such understanding will steel Meno’s resolve to be virtuous in the face of temptation whereas a faulty understanding will cause him to falter. For example, I might resist trying heroin because my parents told me so, but I’ll be much more likely to reject it if I see its effect on others and learn the staggering statistics of misery.
is life-changing. Am I to change my life with the academic wind?
correct role in the atoms of the tree and vice versa due to some bizarre atomic property. When we look at my friend and the tree, however, it certainly doesn’t look that way. It looks like both are totally solid, filled-in objects that smack into each other. In other words, the world is a lot weirder than it initially looks.