Are "will" and "love" metaphors?

In response to the question: is love a “theological metaphor” for physical light & will for gravity?

answer: Maritain would define "goodness" as a "transcendental" property of being; an aspect or facet of being present in every KIND or SPECIES. The "will" is a faculty or power or capacity of (possessed by) the "intellect". The intellect is (in Aquinas-Maritain) a sort of "organ of being", the same way the eye is an organ of the visual spectrum and the nose, olfactory. When Maritain says "good", he means "being relative to the will"; when he says "will", he means the power of the intellect that relates to being as desirable or "good".

Folks like Kant will come along later and argue that more-than-empirical data the mind encounters, such as "being" (or being-as-desirable, aka "good") must be a fiction imposed subjectively on sensory input. They argue this because "being" is, as stated, a "transcendental"; we find it in one kind of being, but even IN THAT SAME INSTANCE, we find something MORE (we find other beings "actually and implicitly/confusedly contained", as they technically put it). Being is like (to use Maritain's language) a "liquid crystal", like in opening any "blade of grass we find a bird greater than the world".

"Nominalists" in the broad sense, including Kant (vs realists like Maritain) go on to argue on this basis that "being" can't be known from individual sensible things and is a subjective form of thought only. Maritain and the realists will retort that being is a "dogmatic" presumption, an "irrational" of all experimental science, you gotta take it for granted to get the ball rolling. It is a foundational and certainly deeper-than-experimental layer of the onion of reality. Every time you measure or sense something, your senses grasp a tangible characteristic OF an (abstract-intelligible, more like like numbers, not sensible like colors) existential core, of a "being" (unifying the property you measure with many others through time in distinction from other substances). Meanwhile measurements further suppose some THING behind a measuring instrument, a correspondence between the characteristics measured by the instrument and the measured thing, between the measurer and the instrument, etc.

So, for these reasons, we can't say "love" and "will" are metaphors for physical properties/processes or empirical science. Indeed by Maritain's scheme, heat would be a specific case of "loving" (being tending to a good). Maritain actually says in "preface to metaphysics" that every being (or "agent", being considered in faculty, as a reference to action) is nothing but "a reference to or 'love' of some good" (or being-as-desirable). "Love", while having aware examples, is in basest definition the tendency of being toward other beings or states of being. The goal of this tendency is determined in each case by the configuration or nature of the agent; "a plant is a radical love of vegetative growth, fire if burning, birds of flying and singing".

It is lastly worth noting that these are all concepts derived from Aristotelian philosophy (NOT Aristotelian empirical physics such as it was, a point Maritain is adamant on), and therefore predate Christianity and the Catholic Church by a while. Aquinas did certainly apply this Aristotelian metaphysical framework to the interpretation of theological ideas such as the Trinity (circa 13th century, though disciples until now), but being-as-desirable (loveable re the will) would be deemed by Maritain-Aquinas a subject of natural philosophy, not theology, something Aristotle and Avicenna knew about too. The difference between philosophy and theology being that theology uses reason to treat revelation (ideas like "God is Triune or became incarnate"), while philosophy uses reason to treat the natural-ontological universe (up to and incl the first cause), subjects like being, causality, knowledge.