Theorem:
If something is defined as existing only subjectively and no human being has a subjective view of said thing (what I here call “perception”), it can be said to not exist objectively and therefore not exist at all.
Proof:
If something only exists in human thought and no human mind (however you wish to define it) has ever been infected with this thought, then we can say that this thing does not exist objectively.
Let S% represent a statement which is defined to only exist subjectively. By this I mean that the very definition of existence of this thing is our perceiving its existence. Let n be the total number of humans in existence in all of space-time for all of eternity. If n=1 (that is, only one human has, is and will ever exist) and this sole human does not ever perceive S%, then S% can be said to not exist objectively in all of space-time for all eternity. Humans are the only beings which we’re concerned with here because it is our subjective mind that is in question. Therefore we can conclude that in the case of n=1, if something doesn’t exist objectively, it doesn’t exist, period.
Now let n>1 (that is, more than one human has, is, and will ever exist), then we can easily expand the n=1 case to take this into account. Let Hk represent the k‘th human. Here k runs from 1 to n. Let Hk.S% mean that the k‘th human perceives S%. The statement Hk.S% can be applied to Hk for all k from 1 to n. For example, let’s assume S% is the concept of music (which means that the concept of music is something that is said to only exist subjectively). If Bob perceives music and Bob is human #253 then we can write H253.S%=T where S% here is bound by definition and T is true. This can easily be written about all similar statements S% and all humans from 1 to n. Let S%.O mean that the statement S% doesn’t exist objectively. It then follows that S%.O <-> \/Hk.S% FORALL k from 1 to n for a given S%. In words, if not one single human that has, is or will ever exist perceives something that is defined to only exist subjectively, then it can be said to not exist objectively and therefore not exist at all. Once a single human perceives a statement S%, it can be said to exist objectively but it does not necessarily guarantee its existence.