But you seem to go beyond that, insisting that there is in fact no objective reality at all, which makes no sense to me whatsoever. Even if we are all living in the Matrix, the Matrix (or whoever is operating it) must be the reality.
Actually, you have been the ONLY one in this discussion to make this absurd suggestion, I have never mentioned it once....
Actually, at one point you did say:
that would imply the very thing you falsely accuse me of doing, namely stating an objective truth, which of course I do not believe to exist....
Saying that objective truth does not exist is a vastly different thing than saying it is unknowable. Even in the latter case, I would disagree with you (or at least with the implications of your statement), but your position would seem a bit more rational.
You are correct that we have no way apart from our minds to perceive reality. Everything we know or think we know is within our minds, and we have no other frame of reference. Therefore, it is theoretically possible that everything we "know" could be some sort of mental construct, in no way representative of reality. Possible, but highly improbable, in my estimation.
Let's say I come home from work later today to find that my wife has done some housecleaning in my absence. I decide that I am thirsty, so I look for my handy 7-11 giant soda mug, which I distinctly remember leaving on the table. It isn't there, so I look around a bit, and find it in the kitchen cabinet. How did it get there? There are a number of conclusions I could reach, any one of which could be true:
- My memory might be faulty, and I might not have left the mug where I thought I did.
- My wife might have moved the mug in the course of her housecleaning.
- The mug might have developed the ability to move under its own power, and transported itself into the cabinet.
- The mug might have been moved into the cabinet by demons.
- Aliens might have beamed the mug up to their spaceship to study its properties, and messed up the location a bit when they returned it.
- Government black-ops agents might have entered my house using their high-tech 007-style gadgets (so as not to be detected) and moved the mug in order to confuse me, thus making me ripe for subservience to the New World Order.
There are certainly other possibilities that could be imagined. But the question is, how likely is it that any given possibility represents the real situation? Most of us would opt for #2, or possibly #1. A Jehovah's Witness might also give some credence to #4. Every scenario on the list is possible, but would any reasonable person conclude that, because they are all possible, they are all equally probable? Clearly, the vast majority of rational people would choose either option #1 or #2. Anyone who made a habit of choosing options like #3 through #6 would probably be seen as having mental problems that needed to be addressed. Rejection by the majority doesn't make those options false, of course, but in the absence of significant evidence in favor of them, experience has shown us that they are highly unlikely.
Similarly, though we can imagine Matrix-like scenarios in which our perceptions are routinely deceiving us about the nature of reality, there is no reason to believe that this is the case apart from any evidence supporting that theory. You said that:
ALL EVIDENCE points to the FACT that everything we KNOW is within our mind, mental inventions
But there is a difference between saying that everything we know is in our mind, and saying that everything we know is "mental inventions." Rationality would lead us to the conclusion that, absent evidence to the contrary, what is in our minds is there because we have perceived what really exists outside our minds, not because we have 'mentally invented' it. Any other theory is an extraordinary claim, requiring extraordinary evidence to back it up. The fact that we can conceive of other scenarios does not mean that they are in any way probable.
And, I think the point I made earlier - that such thinking is not usually applied in real life (refer to my bank teller illustration in a prior post) - is yet further evidence that your theory does not hold water. A good theory should be applicable in practical ways.