To be ontologically parasitic, a thing must exist only in reference to another thing.

For example, in the excellent video "How Many Holes Does a Human Have?", holes are identified as ontologically parasitic. They cannot exist without a thing to reside in. E.g., the holes in a block of Swiss cheese can only exist if that block of Swiss cheese exists. The Stanford Encyclopedia of Philosphy has a pretty interesting article on this as well.

The Stanford encyclopedia also identifies boundaries as being ontologically parasitic; they of course, cannot exist without two objects to be separated by the boundary itself.

I find this topic fascinating, but I'm struggling to think of more examples of this phenomenon. Can you think of any more examples? Are there any papers or books discussing this concept more in-depth?

  • 5
    It depends on one's ontology. Shapes and colors are arguably parasitic as they do not exist apart from what they are shapes and colors of. Thoroughgoing nominalists, like Quine, dismiss all properties and relations as parasitic, see SEP, Relations. Mereological nihilists do the same with composite objects, like tables and chairs. There are no tables, on this view, only "simples arranged tablewise", as van Inwagen put it, see mereological nihilism.
    – Conifold
    May 5, 2020 at 10:23

1 Answer 1


I'm including a means by which to determine the existence of an ontological parasite. Incidentally, Racism is a parasitic term.

First, all nouns in language are either PHYSICAL or NON-PHYSICAL AND have either a DEPENDENT EXISTENCE or an INDEPENDENT EXISTENCE. These combinations of each term will dictate which terms require which combinationws to exist, if any.

A HOLE, a DENT, DARKNESS, RACISM, abuse, anger, evil, are all parasitic although their hosts differ slightly.

-NON-PHYSICAL/DEPENDENT = ABSTRACTION - is the combination for a parasite.

'Your yard" and "your '72 Impala" are each PHYSICAL/INDEPENDENT, they can exist alone as hosts. -A hole, a dent are each - NON-PHYSICAL/DEPENDENT. This is the combination that defines a parasitic/host relationship. (Non-physical because they have nothing in them. Dependent because they exist as abstractions of Yard and Impala)

LIGHT and DARKNESS have the same relation as Yard/hole and Impala/dent.

(Racism) PHYSICAL/DEPENDENT – is the combination for love, virtues, meaning (PHYSICAL since we cultivate them but DEPENDENT on our minds and bodies to exist). Racism is not a Physical term. It exists only as an abstraction. It is merely a conceptual term that refers to the absence of Acceptance, Tolerance, Compassion and maybe others. It exists only as a potential within these terms.

Racism -NON-PHYSICAL/DEPENDENT = ABSTRACTION of Acceptance, Tolerance, Compassion.

Anthony B

  • I don't quite follow how you're defining "physical" here. For example racism in the second to last paragraph is physical "because we cultivate them"--what do you mean by that? And the light/dark relation: I can certainly see how that has the same relation as yard/hole (and indeed shadows are another good example of parasites) but does that mean light is physical and shadow is non-physical?
    – Zaya
    Jun 9, 2022 at 14:14

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