Mereology: does being inside something mean it is inside?

Question

When we speak of an individual having a property we nominalize the predicate expressing the property we take to be constitutive and ascribe the instantiating properties to the individual thus created. There is, however, no deep ontological reason why we could not change our view of what the constitutive and what the instantiating properties are, and thereby describe the very same situation in terms of different individuals and properties. But if we accept this picture of ontology it is evident that we are not obliged to infer the existence of a substratum or underlying individual from the existence of a quality.

https://plato.stanford.edu/entries/nagarjuna/

I take this to mean that the subject and predicate are reversible. So a round apple is both an apple that is round, and a round shape that is an apple. Does it mean then the relation of being "in" another thing is also symmetrical? If a patch of red is in my visual field, then my visual field is inside that red.

1. Surely an effect is in the action of a cause: then the action of a cause is in its effect. This sounds like 'no causation', and how I read Nagarjuna.
2. Whatever is essentially in the world can only end if the world does, because the world is also essentially in it. This seems to me to be the meaning of 'rebirth'.

I think it's a mereological question, about parts and wholes: whether or not everything is - in reality - a part of everything else.

Concerning the antisymmetry postulate (18) [Two distinct things cannot be part of each other], the picture is even more complex. For one thing, some authors maintain that the relationship between an object and the stuff it is made of provides a perfectly ordinary counterexample of the antisymmetry of parthood... Sanford (1993: 222) refers to Borges's Aleph as a case in point: “I saw the earth in the Aleph and in the earth the Aleph once more and the earth in the Aleph …”. In this case, a plausible reply is simply that fiction delivers no guidance to conceptual investigations: conceivability may well be a guide to possibility, but literary fantasy is by itself no evidence of conceivability (van Inwagen 1993: 229). Perhaps the same could be said of Fazang's Jeweled Net of Indra, in which each jewel has every other jewel as part (Jones 2012).

https://plato.stanford.edu/entries/mereology/

Answer 1

But if we accept this picture of ontology it is evident that we are not obliged to infer the existence of a substratum or underlying individual from the existence of a quality. https://plato.stanford.edu/entries/nagarjuna/

I take this to mean that the subject and predicate are reversible.

I believe you are reading the quoted conclusion wrong. Not inferring an individual, which means a subject, from the existence of a quality, doesn’t mean the subject and quality are reversible, it means that there doesn’t have to be a subject. Or more precisely, it means that the quality’s existence isn’t necessarily proof that there is a subject entity that has that quality. This logic is based upon a change from the extant paradigmatic understanding of reality as a material dualism to something different:

There is, however, no deep ontological reason why we could not change our view of what the constitutive and what the instantiating properties are…

Here it is being explained that a logical analysis is ultimately framed by our paradigm, and paradigms can be switched.

But if we accept this picture of ontology it is evident that we are not obliged to infer the existence of a substratum or underlying individual from the existence of a quality.

The quote above is saying that there is no ontological reason why we can’t have a paradigmatic understanding in which there are no entities — subjects — though there are qualities that can be experienced.

Saying that because I see the color red, there is an entity that is ‘redness’ works in one paradigm, but there is this other paradigm that Nagarjuna was alluding to (Emptiness) in which redness is not an entity, and the appearance of red does not require, nor is proof of, an entity that is red.

I hope this helps.

Answer 2

Sounds like some useless, intellectual gymnastics - just apply mindfulness to the thinking process or the doubt that arises instead of getting caught up in concepts.