” abstractions do not exist “out there” they only exist in the mind.”
As far as I know,
That we can be certain about existence comes from our ability to perceive that which is extant.
That we can perceive anything is only through the mind.
The mind exists because the mind perceives is own existence.
Therefore our existence is metaphysical.
Therefore we can not be certain that physical objects exist independently of the mind.
Axiom: knowledge is attained through, and only through, Perception.
It is through the mind, that I know physical objects exist independently of my ability to perceive.
Therefore something can exist independent of my mind.
Since all objects, physical and metaphysical, first begin in the mind and objects which are known through the mind can be perceived to be independent of the mind, then metaphysical objects can exist independently of the mind.
If I consider some things to be self-evident, such as; there are physical objects that exist in the universe and their existence is independent of our ability to perceive them. If every conscious being* died (assuming that to be the end of consciousness), I feel certain that the physical objects, and for that matter the universe itself, would continue to exist, independent of an ability to be perceived. Now, the laws and mathematical axioms, if true, that govern the universe and those objects contained in, which are metaphysical, would not be expected to cease without our ability to perceive them.
If in fact, it is true that metaphysical objects exist only in the mind then the metaphysical objects and the physical objects they govern would disappear with the end of consciousness. If so far, you believe I have gone off the rails, you might stop to consider, what is Force?
I believe the implication here is; If future existence of objects is contingent on the mind and its ability to perceive them then the same too the existence of past objects. What should be immediately obvious about this is that consciousness would not only be the creator of existence but also the sustainer.
*Except 1. As it is, we know that existence seems to be all in the mind but not in our minds because people could not justifiably state that they are the creator and sustainer of existence. If my axiom is correct then something would have to first perceive itself in order to account for existence. There can only be one such entity because we can only perceive one existence. It can have no predecessor because an infinite regress has no beginning.
I don’t mean this to be a proof of anything. I haven’t studied the philosophers nor am I certain that I have managed to stay logically consistent. I do believe I have offered something, at least, worthy of consideration.