You learn about the world by forming a series of abstract categorical relationships about it. This literally defines the way reality appears to you. There is no wall for you to bump your nonexistent head upon unless categorical relationships exist between concepts such as "head" and "wall" and "you.". Without subjectivity, all that objective information is rendered completely unintelligible and is therefore meaningless.
This is probably the main point of disagreement for us. I believe that, regardless of what concepts I might have about heads, walls, and me, that that wall will exist there, and will stop all heads from going through it if they attempt to. I.e. objective reality exists regardless of our subjective concepts, and we just make subjective meanings and concepts about the objective reality that exists around us as a way of trying to understand and categorize it. Thus there is a single objective truth, which is that stuff exists in whatever form it exists. We just try our best to interpret and conceptualize it based on our limited perception. To ignore or throw out this truth would mean basically danking the whole world's existence.
EDIT: Reading your stuff in the contexts of just your stuff, I'm realizing I may have been totally danked in the head regarding my views of what you are actually trying to say, conflating your and his claims to be saying something similar. Am I right that you are actually saying two completely different things, and he's just nuts?
1) I think the problem is that I'm making a fine distinction that you're not picking up on. We both agree that there is a single objective truth regardless of what we think that truth is. I think we can also agree that there is objective information out there, and this objective information makes up walls and such. I won't even necessarily contend that the information that makes up the wall ceases to exist in a Universe with no observers and no subjectivity. The fine distinction I'm making is this: if information is not being communicated, then that information is utterly unintelligible. If the information is utterly unintelligible, then we cannot call it a wall because a wall is intelligible...it has 'wall-ness' so-to-speak. When you remove all observers from the Universe, you remove all entities that are capable of rendering the available information in an intelligible way. And while this information might somehow continue to be available absent of any observers, we cannot in any way say that there will still be a 'wall' anywhere because the Universe you're describing has no way to communicate or render 'wall-ness'.
2) As weird as it is, I both think he's nuts and I think he says some accurate things. Unfortunately, it's pretty easy to make any statement and convincingly argue it to be true in one context or another. The problem is that when one starts switching the context of their argument, contradictions are bound to arise.
Dank seems to be saying that because anything can be true in a certain context (e.g. If Bob likes pizza, and if Mike likes pizza, then Bob is Mike...to the extent that they are both pizza-likers). He also seems to be suggesting that because anything can be true in a certain context, you can discover or even manipulate truth if you just "believe" in your own ideas with enough intensity. In contrast, I'm asserting that 1) there is a set or context that contains all other sets and contexts, thereby uniting all subsets within a common linguistic or mathematical landscape, and that 2) there is a way to act as though you yourself are reasoning from this greater set about all lower sets, thereby creating a model that remains internally consistent at the highest possible level of generality.
Dank does, however, seems to place an emphasis on learning through direct experiences (which is why he uses LSD and such) to uncover truth in a different way. I absolutely believe this approach is valid, and I would in no way rule out "tripping" as a valid means of accessing otherwise inaccessible information and/or re-rendering the same information in a new way. I personally think our minds are more or less 'tuned' to a certain frequency of energy at one time or another and that there are ways of fucking with the dial. He seems to share a similar belief (he advocates drug consumption while I advocate meditation).
