If we perceive it, it is no longer existing "external to the self".
No, our perception of things with objective existence is distinct from, is not the same thing as the things themselves. Otherwise there'd be nothing for our senses to perceive but our own imaginings, and I'm not a solipsist.
And since the "self" is the subject of our subjective experience
The brain monitors and edits the incoming sensory data and interpret the parts it deems relevant. Is that what you're referring to?
our perception of this "external world" is a subjective perception (creating a subjective conception of reality, in our minds)
But we have many ways of maximizing our objectivity. Other things being equal, a video will beat witness testimony in court, for example. Part of science is repeating experiments that others have done to confirm their results. Truth is our best opinion for the time being, but it still functions as truth, and it can generally be confirmed or confounded by anyone else who cares to compare it to objective reality.
What you are defining as being "the self" is your own body. But this is not accurate. What is the "self" is not just our bodies, but our cognitive being. It is our self-awareness. And that includes our subjective experience and understanding of the world in which we exist.
No, what I'm defining as the "self" is the brain's sense of self, the me that looks out through my eyes, that speaks or types this &c. Though as I said, I can use the word "I" to refer only to me=sense of self or to refer to me=brain+body.
But our subjective experience and understanding does not include all that exists. It only includes that which we have experienced and recognized, of that which exists. The rest is 'objective reality'
We don't experience all that we understand to exist. We look around, we go touring, we hear tales and reports, we read, watch docos, observe, encounter, and so on. But having objective existence, being in nature, existing external to our mentation, being real, are synonyms. There really is a world out there and our senses really do tell us about it. That our interpretations are subjective doesn't alter the reality of external reality.
And by it's very definition, it must remain there; beyond our cognitive grasp.
You must be using different definitions to me.
What you are describing is the presumed relative truthfulness of functionality.
I thought I knew what 'functionality' meant, but I see I'll have to ask you for your definition.
The problem is that when we think we have access to "objective reality", we start thinking that relative functionality is "the truth".
As I said earlier, either to you or in another post, 'truth' means correspondence with objective reality, and so there's an objective test for truth. But eg in matters explored by reasoned enquiry, like physics, truth is our best opinion for the time being, not anything absolute. As I also said, there
are no absolutes outside this sentence.
And when we espouse science as the primary means of determining this relative functionality, we have entered the error-prone philosophy of "scientism".
I'll wait till you explain your use of 'functionality' before I respond to that (though I'll flag that scientism is not the same thing as a preference for evidence-based conclusions and can easily sound like a cheap shot in conversations of this kind).
We are not testing it against reality. We are only testing it against our subjective perception and understanding of reality.
Think of it as a consensus of people with the qualifications to have credible opinions: we're testing X's report about reality against the reports on the same reality from those people, we're after the best opinion available to us.
The "so what" is called honesty, humility, and open-mindedness.
I'm open-minded only up to a point. When the claims aren't backed by evidence, when there's no reply to my request,
Really? Show me, my skeptical side seems to dominate.
What has science ever done to make humanity wiser, or morally responsible to each other or the world?
It can help clear out superstition, bring discipline and clarity of thought, reply to cigarette companies and global warming deniers, and make good things as well as bad things possible. Be it noted that religion has led to many many many more wars than science has.