Airplanes exist because they are made of something physical. We know that Airplanes are Airplanes because they have physical properties. What I’m talking about is thoughts. They have no physical properties and they do not exist beyond the mind that is thinking them.
My first thought is that you’re taking on way too much at once. Iows, you need to study the philosophy a lot more to satisfactorily answer the kind of question you are asking. This is where Peikoff’s book OPAR comes in handy.
But, here is my crack at it for now, keeping in mind that I’m not the authoritative source here.
All valid ideas can be grounded in reality. Reality includes all things which exist and their actions.
“Objectivity” is a *process* of thought. It’s a process you go through to achieve valid knowledge. Iows, the phrase “objective reality” is meaningless. Reality is the standard of objectivity, and objectivity is the process by which you try to meet that standard.
Objective knowledge, as David referred to, is a result of our awareness of those things we pick up through our sensory-perceptual apparatus. Our conceptual knowledge, if valid, is based on a logical integration of our sensory-perceptual data.
For instance, I know about chairs, because I’ve observed lots of instances of chairs. I know about trees for the same reason. Knowledge on the conceptual level is built from many concrete instances of things like chairs and trees.
At the end of the day, our thoughts do exist in the mind in some state. They are real. The concepts we hold about things in the world are held in the mind as a certain kind of relationship between the things we sense and our sense organs. Exactly how they are held is a question for science.
Since thoughts dont exist outside of the mind they are subjective.
That’s not what Objectivists mean by “subjective”. This is where modern philosophy has defined objectivity out of existence. One is subjective when the knowledge one holds is not based in evidence and reason. Iows, when one is whimsical about knowledge, then the knowledge could not be valid. If I say there is a moon, then that is objective knowledge, based on direct sensory-perceptual evidence. If I say there is a kangaroo space alien on the moon that is arbitrary and subjective, i.e. not based on sensory-perceptual evidence, but entirely made up.
If thoughts had somehow become a physical property of the universe then they could be considered objective.
Well, thoughts are necessarily physical, or the result of a process, which requires physical things. The knowledge that the knowledge is of, however, is the result of an evidence based relationship.
This is a good question. The only problem is how much you are taking on in one step. Way too much at this point.