How is 'metaphysics' 'theories of the connections between what we see and what we can't see' and connected with 'ladder rungs'?

Question

Source: The Complete Idiot's Guide to Literary Theory and Criticism (2013 1 ed). p. (between 21 and 90, but I can't remember).

One of the most significant influences in this regard was the third- century philosopher Plotinus (pronounced plo-TYNE-us), who elaborated on several of Plato's ideas concerning metaphysics, or [1.] theories of the connections between what we see and what we can't see. His work expanding on the [2.] "ladder rungs" or levels [End of 2.] that lead from physical human experience to the realm of the pure soul was particularly influential for Christian and other religious doctrines.

DEFINITION

[3.] Metaphysics describes the kind of philosophy that investigates "first principles" or the truths that must underlie existence. [End of 3.]

The author isn't a philosopher, but has a BA, MA, and PhD in English.

I accept 3 as a correct definition of metaphysics, but not 1.

4. Doesn’t 3 differ from 2? How exactly is 3 related to 2 ('ladder rungs or levels’)?

Answer 1

See Plotinus :

Plotinus (204/5 – 270 C.E.), is generally regarded as the founder of Neoplatonism. He is one of the most influential philosophers in antiquity after Plato and Aristotle. The term ‘Neoplatonism’ is an invention of early 19th century European scholarship... In fact, Plotinus (like all his successors) regarded himself simply as a Platonist, that is, as an expositor and defender of the philosophical position whose greatest exponent was Plato himself.

The three basic principles of Plotinus' metaphysics are called by him ‘the One’ (or, equivalently, ‘the Good’), Intellect, and Soul. These principles are both ultimate ontological realities and explanatory principles. [...] A central axiom of that [Pre-Socratic] tradition was the connecting of explanation with reductionism or the derivation of the complex from the simple. That is, ultimate explanations of phenomena and of contingent entities can only rest in what itself requires no explanation. Thus, what grounds an explanation must be different from the sorts of things explained by it.

Thus, in very rough terms, the aim of metaphysics is to found the "simple" principles (the Platonic Forms) that explain the complex phenomena.

Phenomena = what we can see; Forms = what we cannot see.

For "ladder rungs", see Emanation from the cosmological point of view as well as Contemplation : "a force capable of producing the necessary tension amongst beings in order for there to be at once a sort of hierarchy and, also, a unity within the cosmos."

Answer 2

A ladder and its rungs are symbols being used to convey the ideas behind, so that the listener can understand the ideas by analogy.
One side of the ladder is the "physical" (what can be seen), the other side is the "metaphysical" (what can not be seen), and the "rungs" are the "connections and levels" between both realms.

Answer 3

Historically speaking, -1- is the most accurate and precise way to characterize the classical Greek distinction between physics and metaphysics. Plato's own ontological distinction was between the "the visibles" or the "the visible world" and "the intelligibles" or "the world of ideas". (You can quibble over whether "perceptible" or "visible" is the best general translation, but your source knows what he's talking about — as did Plotinus.) This visible world corresponds to Kant's "phenomena" or to nature (Greek physis). The term "metaphysics" for what is "beyond nature" in this sense is due to Aristotle.

-2- is the most complicated of the definitions because what exactly it means is most tightly interwoven with the changes/developments in Hellenistic philosophy from Plato to Plotinus. Plotinus was writing for an audience that had much more... specific expectations about the problem these "ladders" were supposed to solve. I will skirt around your question about 2<-->3 relation because the drift in what -2- means makes the question about how -2- is related to -3- unproductively complicated.

But, if you can accept broadly that Plato (at a minimum) did see the "visible world" / "world of ideas" dichotomy as central to understanding knowledge and the function of philosophy, then it will suffice to explain 1<-->2 to say that the "ladders" between levels correspond to interactions between / cognition of different ontological grades, and it will suffice to explain 1<--->3 to say that true philosophy or theoretical reflection involves grasping idea-objects that can then function as first principles (prota or archê) in the scientific approach to understanding subdomains of the visible world. If this account of the 3 <--> 1 <--> 2 relationship seems comprehensible, then that should give you at least a vague sense of why -2- and -3- would be related to each other.