I think there is a confusion here. We do attach truth labels to ideas ("true", false" etc.) but that does not mean that truth itself is a label. What we usually mean by "truth" is a fact of the matter that an idea somehow does correspond to some fact in the world. That is, having a particular idea is dependent on a mind having this idea, but once a mind has a particular idea then whether this idea is true or not does not depend on any mind. It does not depend on anything. It's a fact.
Of course, that's just the common notion of truth as people use it in everyday life and various people can entertain their own notion of it but if you're not talking about the common notion then I don't know what you are talking about.
What is to understand? If the idea maps to reality, we slap the truth label on it. If it contradicts reality, we slap the false label on it. If you don't like using the word "label" then fine, but true and false are still properties of ideas, while absolutes are independent of sentient minds.
Further, our minds are simply too limited. There is a limit to what we can know, and everything we know has to pass through the filter of our senses, our language, and our deeply flawed minds, so even if such a thing as absolutes were possible, we would have no way of knowing if anything we know actually is an absolute.
I would agree only for truths about the material world. For example, I accept that I don't actually know whether there is a material world. But I would disagree concerning truths about our minds. The thought "I think therefore I am" is a truth.
Substance dualism is an untenable position. Proponents of substance dualism have yet to offer a single good reason to need "non-stuff stuff" to explain anything.
"I think therefore I am" is merely an internal observation. Since at the moment you cannot show me your thoughts, you cannot prove any of your purely internal observations to anyone else. You know you think, but you don't know anyone else thinks, and no one else knows you think. This leads us to solipsism...
Lastly, we don't even know if reality is real. We can't know that. This is the only place that solipsism is relevant. Since we can't say that reality itself is real, we can't say that anything we know is an absolute.
Literally, I can't even imagine what it would mean to say that reality is not real. That's a contradiction in terms, right? Also, the Cogito gives an example of something real we know whenever we think so we also know that reality exists.
EB
You could be a brain in a vat, and maybe the rest of the world is part of a sophisticated simulation fed into your brain by a machine.
Or maybe even your brain isn't real. Maybe you're just a piece of software running on a vastly sophisticated computer simulation in the future, on an alien planet, or even another universe. If this is the case, then we don't even know if the laws of physics/reality are the same in the real world outside our simulation, since everything we know about "reality" comes from observations from within the simulation. Every single thing we know is therefore suspect.
It's not inconceivable that in the future humans will have computers sophisticated enough to simulate entire worlds full of sentient people. If so, it is not hard to imagine those future humans running a very large number of simulations of the past in order to better understand the past. If this is the case, then the number of simulated humans living in 2015 would vastly outnumber the real human beings living in 2015. Assuming that computer science continues developing at its current pace, aren't you statistically more likely to be a simulation of a human than a real human? How would you know if you were real or part of a simulation?
Of course solipsisms are absurd. That's the very nature of them. However, since we can't actually
prove that reality is real, we can't really say that anything we know is 100% true even if it were possible (and I really don't think it is) for our flawed minds to grasp such a truth.
I know it's tempting to think in a binary way: everything is either completely true or completely false. After all, every single thing our teachers ever asked us to understand was treated as being absolutely true or absolutely false. However, our teachers had to deal with facts this way because they had to plow through a large amount of material in a short amount of time. Here in the real world, we have no choice but to accept that every idea we have is on a sliding scale between "almost certainly true" to "definitely false" and everything in between.
Aside: on the topic of solipsism, it's entirely possible that our entire universe is a 4-dimensional projection of a 2-dimensional surface of the event horizon of a black hole in another universe. If so, then reality definitely isn't what you think it is.
