I'm designing a learning program and I need to come up with a set of terms for the "objects" the user interacts with.

In a concise way, I'd like to come up with two terms that describe:

  1. a property (like color, if applied to a fruit)
  2. the set of possible values for this property (like red, yellow, green, if applied to an apple)

Property seems like a fitting word here, but this raises a bit of trouble: what, then, are red, yellow, green? Also properties. So how to differentiate the class from the set of all instances?

It seems difficult to me, perhaps due to my insufficient understanding of the philosophical nomenclature, to draw a distinction between the concrete set of all members of a class and the abstract class itself. Certain concepts relevant to philosophizing seem to have made affordances for this. For instance, man in the following:

One small step for man...

vs men in the following:

Either men will learn to live like brothers, or they will die like beasts.

Any ideas? My best stab at would be something like:

Property ------- Value

  • See Properties (aka: attributes). Commented Nov 24, 2020 at 8:55
  • 1
    The relation of predication: a property (an universal) is predicated of an object, maybe is not that holding between properties of different levels of generality: color vs red. In this case (also if some philosopher proposed to say that color is a property of red) we may say that a concept (property) is subsumed into a more general one. Commented Nov 24, 2020 at 9:00
  • Class and set are abstract objects corresponding to a concept: the individual men belongs to the set of humans (fall under the concept man). Commented Nov 24, 2020 at 9:01
  • @MauroALLEGRANZA. You mean the individual man?
    – David J.
    Commented Nov 24, 2020 at 9:23
  • @MauroALLEGRANZA. Are you making a suggestion here? It's hard for me to tell
    – David J.
    Commented Nov 24, 2020 at 9:24

2 Answers 2


In logic and various other areas the terms type and token are used.

From the WP article type-token distinction:

The type–token distinction is the difference between naming a class (type) of objects and naming the individual instances (tokens) of that class.

Thus, in the example you give of colour, the type colour has associated tokens including red, green, and blue.

  • Since asking this question a couple of years ago, I've arrived at the same approach.
    – David J.
    Commented Aug 17, 2022 at 11:01

If the attribute is fuzzy, the number of members of the class must be more fuzzy because there must always be an additional layer of interpretation about which things fit the class. How many things fit attribute x is actually a separate question entirely, divorced from what x is.

Things are nothing but sets of attributes and boundary conditions and none of it is concrete except in that it is specific Enough for a given purpose. When i say i want an apple, the kind doesn't matter, but when an apple vendor says they want an apple, it matters.

BTW, "One small step for A man, one giant leap for mankind." was the intended quote, explicitly to make that distinction. He screwed it up.

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