unphysicality

This is a strictly philosophical post on physical and non-physical objects.

I call a thing is physical if it can affect (or had affected) another object that is physical, or vice versa.

If I define the Earth as physical, then it naturally follows that humans are physical, because humans can affect the Earth. Similarly, the Sun is also physical because it can also affect the Earth, etc. Therefore, defining any part of the universe as physical automatically implies that everything in the universe is physical.

By convention, the everything in the universe is physical.

A thing is non-physical if it is not physical.

Question: do non-physical objects exist?


The problem with this question is how I should define existence. If I define existence in the narrow sense that "A thing exists if and only if it is a subset of the universe", then it naturally follows that non-physical things do not exist.


If I define existenece in the obscure sense that "A thing exists if it is a subset of some entity greater than the universe" (whatever that entity is), then the question can be answered with a bit of logic.


Suppose a non-physical thing A exists. Since A by definition can never, had never affected, nor can be affected by, nor had been affected by a physical object, the thing A is irrelevant with any physical objects, i.e. us. Therefore, the existence of non-physical objects is of no interest to us, nor can we ever find out their existence. So the answer is: we can never know whether non-physical objects exist, and their existence is entirely irrelevant to us.

Alright, that's my short anecdotal philosophy post. I'm not sure if my logic/definitions are valid, but that's my conclusion so far.