Originally posted by Hoth
I'm not going to go through responding to everything you said that I disagree with, since it's clear enough that every individual matter of disagreement is based on the basic disagreement about subjectivity. Namely, you don't think there is such a thing as the subjective distinguished from the objective. That's the basic issue in dispute.
No, you still don’t understand my position. I do indeed allow for the subjective and the objective to have distinct definitions. In my view, the subjective is that which is perceived without having been confirmed. Objective is something that’s confirmed – in such a way that it’s something that independent observers would agree on. However, there is no difference between the subjective and the objective in terms of the mechanics of the mind.
See
http://www.sciforums.com/f35/s/showthread.php?s=&threadid=5554&perpage=20&pagenumber=2 . As explained there, time and space are illusions, they don't actually exist -- and theoretical physicists seem to agree on that. So, if nothing is actually there, why do we have this illusion of something being there? The simplest logical conclusion to draw is that the illusion is caused by perspective.
Your analysis is flawed. If perspective was the only source of this “illusory” universe that you imagine, then you would never be caught by surprise when a stray bullet penetrates the back of your skull and ends your existence. Before you were born your perspective didn’t exist – yet you were born. Even when you’re unconscious things happen to you (your body) – regardless of whether you have the presence of mind to observe that or not. Far away in the constellation of Orion stars are being formed even without you being aware of it.
Relativity does not support the argument that reality is an illusion. Rather, within a relativistic framework you may consider
dimensional measurements to be illusory (although even that’s a questionable characterization indeed.) In a relativistic universe your measurements of some event’s coordinates may not agree with the measurements of another observer (though the “disagreement” is very deterministic and systematic.) However, you will still both agree that the event
has indeed occurred. That aspect of existence (i.e. existence itself) is not illusory. Neither is the presence of dimensionality in the universe (i.e. the very coordinates you’re measuring). Neither is the existence of natural laws that govern the universe independently and irrespectively of any observer.
Realize: the brain is a space-time object.
That is rather an objective truth, isn’t it?
From that fact it's clear that without perspective, the brain does not exist.
Except you have it backwards. It’s not perspective that defines the brain’s existence. Rather the brain’s existence within spacetime grants it its coordinates and velocity, and thereby imbues it with what you seem to call “perspective”.
Accordingly there’s no need for me to address the rest of that particular argument of yours.
First, here's a quick summary of what subjectivity is about:
http://www.ec3.com/Upperized/SELF.HTM
You’ll have to forgive me if I don’t accept a particular philosopher’s take on reality as The Absolute Truth With a Capital ‘T’.
It explains there exactly why it's so hard for people to grasp: "The empathy criterion constitutes a rhetorical blocking position ... that tends to keep us from thinking about subjectivity at all."
That is an idealist difficulty. It does not exist for materialists.
Also mentioned in there: "never treat information as being real on its own; its only meaning is in its use by people."
Absolute rubbish. Physicists routinely use the term “information” to refer to a system’s instantaneous state. When systems interact information is said to be transferred between them. Physical processes are well known to occur quite without anyone looking on and trying to make sense of them.
And the summary at the bottom there isn't bad either: "A 'self' is a mental model, and a mental model is a virtual machine over neural machinery operating in spacetime."
That’s what I claim as well. It’s going back to my original analogy equating the brain with computer hardware and the mind with the instantaneous state of the brain.
Here's Nagel's most famous essay on the subject, titled "What is it Like to be a Bat?":
http://www.silcom.com/~teragram/bat.html.
The gist of it, which he explains much better than I, is that for physicalism to be true you must be able to objectively describe the experience of
being something which you are not.
While I agree with your summary of the essay, I disagree with that presumption. The root of the presumption is that the self is an irreducible, abstract entity. However, such an assumption is not justifiable. If, as I suspect, the self is merely a decision-making hub within the brain then it is entirely expressible as a string of bits (just as is anything else in the universe) – in other words, it is expressible as information. Now, as Turing had shown and computers have demonstrated since, information can be both an input and an algorithm. Therefore it is physically possible to represent the self in a way appropriate for human perception. Given a hypothetical technology to map the brain’s dynamic state at atomic precision and millisecond resolution, and then given adequate analysis, it will be possible to point at a neuron or collection of neurons and say here is your sense of self, here is your emotional state, here is what you’re currently thinking about, etc. With the key nodes of the self so identified, it would then be possible (given another hypothetical technology) to directly feed non-human input from the corresponding cognitive centers of other animals into a human’s conscious mind. That would be a direct way for you to experience what it is like to
be anything, including a bat.