One of the barriers to understanding Scholastic writers like Aquinas is their technical terminology, which was once the common coin of Western thought but is alien to most contemporary academic philosophers. Sometimes the wording is unfamiliar even though the concepts are not. For example, few contemporary analytic philosophers speak of act and potency, but you will find quite a few recent metaphysicians making a distinction between categorical and dispositional features of reality, which is at least similar to the former, Scholastic distinction. Sometimes the wording is familiar but the associated concept is significantly different. For example, contemporary philosophers generally use “property” as synonymous with “attribute,” “feature,” or “characteristic,” whereas Scholastics use it in a much more restricted sense, to refer to what is “proper” to a thing insofar as it flows from the thing’s essence (as the capacity for having a sense of humor flows from our being rational animals and is thus one of our “properties,” but having red hair does not and so is not a “property”). Other terms too which are familiar to contemporary philosophers have shades of meaning in Scholastic writers which differ significantly from those associated with contemporary usage -- “intentionality,” “necessary,” “causation,” “essential,” and “teleology” are examples I have discussed in various places.
And then there are “objective” and “subjective,” which are sometimes used by Scholastic writers to convey more or less the oppositeof what contemporary philosophers mean by these terms.
Hence, contemporary philosophers of mind like Thomas Nageland John Searle describe as “subjective” those aspects of reality which are accessible only from the “first-person” point of view of conscious experience, and as “objective” those aspects that are equally accessible to any observer, from the “third-person” point of view. So, bodily sensations, mental images, and consciously entertained thoughts would in this sense be “subjective” while tables, chairs, rocks, trees, muscles, bones, and neurons would be “objective.” What is “subjective” on this usage is what is withinthe mind, what is part of the “inner” realm of consciousness; what is “objective” is what is without the mind, what is part of the “outer” world of extra-mental reality.
This is, in any event, what Searle characterizes as the ontological sense of the subjective versus objective distinction. There is also an epistemological sense, in which to be “subjective” is to be unduly influenced by emotion, prejudice, and the like, whereas to be “objective” is to be guided by reason and the facts. As Searle rightly emphasizes, to be “objective” in the epistemological sense is fully compatible with recognizing the existence of what is “subjective” in the ontological sense.
Now Scholastic writers would certainly agree that we should be objective in the epistemological sense and that there are both subjective and objective aspects of reality in Searle and Nagel’s ontological sense. But they also sometimes use the words “objective” and “subjective” in a very different way -- indeed, as I have indicated, in a way that very nearly reverses the meanings attached to them by writers like Searle and Nagel.
Hence, in Scholastic literature, something is sometimes described as “objective” when it exists only as an object of thought, but as “subjective” when it exists in a real subject outside the mind. So, for example, that unicorns have horns might in this sense be described as an “objective” fact, because (since there are no unicorns in reality) what is true of a unicorn is true only qua object of thought. By contrast, that a certain horse can run very fast is “subjective” in the sense that its capacity for speed can be predicated of a real subjectoutside the mind.
To be sure, Scholastic writers also sometimes use “objective” and “subjective” in the senses that are more familiar from current philosophical usage. But when they do not, confusion can sometimes result. Hence modern readers of Descartes’ “trademark argument” for God’s existence are sometimes baffled by his talk of the “objective reality” of an idea, since given current usage an idea seems paradigmatically “subjective.” But Descartes was making use of Scholastic jargon that would have been familiar to the readers of his day.
Properly understood, the claims typically made using “objective” and “subjective” in these various senses are perfectly compatible. We just have to keep the senses straight. Hence, if we avoid subjective bias (in Searle’s epistemological sense) we will see that we can be said to have objective knowledge (in Searle’s epistemological sense) that it is an objective fact (in Searle’s ontological sense) that the speed of a horse is a subjective feature of it (in the Scholastic sense), whereas that unicorns have horns is merely an objective fact (in the Scholastic sense) insofar as it is true of unicorns qua objects of our thoughts, which exist subjectively (in Searle’s ontological sense).
“Whoa, hold on! Let me see if I get this. So it isn’t subjective to say that it is objectively true that what is subjective can be objective and what is objective can be subjective. Dude, that is so trippy!”
I know, isn’t it? Like something off Revolver!