A generous friend of mine allowed me to post his notes on Greg Bahnsen’s lecture series, A Biblical Introduction to Apologetics.
2.) Are There “Likenesses” (i.e., Categories/Classes/Universals) In This World?
“Duck” is a universal, “ducks” are not. When we see three ducks on a pond and speak of them as being ducks, we’re referring to something that is not a duck. That is, when we call them “ducks”, that which we are referring to is not itself a duck. The ducks are on the pond, but what we’re talking about is not on the pond. We’re talking about the category to which the ducks belong,
and of which the three ducks are a part. The category (class/concept) is not on the pond. Duckness, as an idea, is not on the pond.
Anything that we talk about that unites particulars is itself not a particular. The three ducks on the pond are particulars (ducks) that are united by one universal (duckness).
There are likenesses in this world, and if there weren’t, we wouldn’t be able to reason. In many cases, reasoning is a matter of finding out that a particular is a member of a class of things. When you have a growth on your hand and go to the doctor, and he identifies the growth as a wart, he’s identifying something that belongs to a certain category. He’s pointing out that you have a particular wart on your hand, he’s not saying that you have wartness, the universal concept itself, on your hand. By the way, when he treats your hand, he’s assuming the future will be like the past. But before he can apply that sort of thinking, he must first say that the thing on your hand falls into a category called “warts”. He’s thinking in universal terms. Likenesses are like relationships. The relationship is not the same as the two things related. When a Bible is on a podium, the Bible and the podium are what are related in that sentence. It’s the “on the” part that relates them. So there’s “Bible”, “Podium”, and the relationship (“on the”). We will focus on a special kind of relationship; the relationship of part of the same class (identity relationship).
The three ducks on the pond are not duckness, they are members of a class, three instances of a universal concept. It’s impossible to reason only about particulars. In the statement “The barn is red”, the barn is particular, and red is universal. The particular barn is a member of the class of things that are red. The barn participates in redness, but is not redness itself, otherwise we could burn the barn down and redness wouldn’t exist anymore. The color red is a likeness (i.e., category/class). There are particulars and there are classes, and when we speak to each other, weput particulars into classes (e.g., “That thing on your hand is a wart”, “That barn is red” etc). Particulars are understood in terms of the classes that they belong to, the likenesses that they have (e.g., “That thing is like this thing”).
What’s the point of all this? You can’t touch any of those likenesses. You can’t touch them, taste them, smell them, see them, or hear them. They’re not in the physical world anywhere. If they were physical things they could be encountered at some point & destroyed. The unbeliever doesn’t believe in anything except what we can experience. If that’s the case, then the unbeliever must stop talking and stop reasoning. When the unbeliever talks and reasons, he refers to things (which on their approach to the world, cannot exist) which are not physical, like names, concepts, categories, classes, & universals. You’ve got to be able to explain this to your neighbor, coworker etc. Unbelievers use categories all the time. We can point to particular instances of redness and touch them, but we can’t touch the category of redness itself. If there is nothing in this world but physical objects, they are all particular physical objects because there’s no such thing as a universal physical object. There’s no such thing as pianoness if only physical things exist, because pianoness is not physical, particular pianos are. If someone claims to have pianoness in their bedroom we can call them on it and say that they couldn’t have pianoness in their bedroom because if it were in a particular place at a particular time, it wouldn’t be a universal.
So when the unbeliever begins to insist that only the things which we can touch, see, hear, and smell exist, you have a way to show him that all reasoning has to stop according to his view, including talking, because there would be no classes, universals, or likenesses in terms of which we could reason.
I call this a “likeness” because the unbeliever’s first out is going to be something like….
Atheist: “I can see that there’s a likeness between those things. That’s what I’m talking about. I see those things and I see that they’re like each other, and what I call that likenessis pianoness or duckness. So there’s only particulars, but I do see that some particulars are like each other, and I give a name to that.”
The Bible says the unbeliever opposes himself, so take a look at how the teeth of his own trap close on him.
Christian: “You say that there are only particulars in this world, but then you see a likeness between them. And what I’d like you to show me is the likeness. Don’t show me the ducks, show me duckness. Don’t show me pianos, show me pianoness. I’d like to see what it pianoness feels like, what it feels like to kick pianoness.” So when the unbeliever says he can see a likeness, you can say….
Christian: “Well you’re seeing something that doesn’t exist, because on your worldview nothing exists that isn’t physical, and the likeness isn’t physical. The likeness is no more physical than “on” is physical. A book can be on a podium, and both are physical, but “on” is not physical. The relationship of identity between things is not physical.” But what if the unbeliever mistakes a category of non-existent things with the non-existent things themselves?
Atheist: “There are a lot of categories that are in the mind of man but don’t really exist.”
Christian: “Then they’re not in the mind of man.”
Atheist: “What do you mean?”
Christian: “If a particular category doesn’t exist, then it can’t be found to be in the mind of man.”
Atheist: “What about unicorns?”
Christian: “What about them?”
Atheist: “Do they exist?”
Christian: “No, but the category of unicorns exists, otherwise we couldn’t even talk about them and identify any fictional thing as conforming to the category of unicornness.”
Question: How are particulars identified?
Answer: Particulars are identified in terms of the universals of which they are an instance.
• If we didn’t put particulars into categories we wouldn’t be able to reason at all. Particulars would only have names, not class concepts. If there were only particular things in this world everything would have to be named in that way and nothing could share names. Think of it as numbers: instance 1, instance 2, instance 3, instance 4, etc, with no relationship between them. It would just be the numbers out there. But then, since there would be no categories, we wouldn’t be able to call them numbers either, because numbers are members of a universal category, and are not physical.
• When we reason about particulars, we have a universal by which we reason concerning particulars in the first place.