It is unfortunate that this one isn't worded as a question. Wouldn't
pass muster on Final Jeopardy, would it? First of all, I'd
like to recast it as "body in a vat"; certainly some sensation and
experience of "reality" occur outside of the brain. Or is this an
illusion as well? "Phantom limb syndrome", where amputees claim
sensations in amputated limbs, gives us evidence of the possibility
of ex-cranial sensations being an illusion, but, for the sake of this
question, I'm not sure the distinction matters. Or, at least I'll
pretend it doesn't for now. I'm anticipating having a rough time with
this question. We'll see.
I'm not sure if the question is asking us to think about the
possibility that all reality is an illusion, or should be taken
literally -- is a body in a vat possible, with simulation of
sensation and experience possible, and, is there any evidence
one way or the other that we are "real", or simply bodies in a
I think the first point is easy to dispense with. If we are simply
bodies in a vat, then certainly at least the vat exists, right,
even if we are unaware of it? Perhaps someone even built it and
connected our body to it, and even maintains the gooey fluid we
are presumed to be submerged in. One could even envision what this
vat may look like by watching The Matrix series of flicks.
So, there is always some reality, even if it is only the
vat, or a regress of virtual imagined vats that at least must
end at something real. I find this possibility philosophically
uninteresting, as do I the possibility of an infinite regress of
virtual vats, or no vats, meaning the entirety of reality itself
is an illusion. In such a case, there would be no meaningful
frame of reference to discuss such a prospect. So, I take as
axiomatic something being real, even if such reality
may have been created ex nihilo as discussed in
So I recast the question as, is it possible we could be bodies
in a vat, with sensation and experience input to our body, and
is there any evidence one way or the other?
Well, of course it is possible. I'm am unaware of any evidence
that rules out the notion. But given that I am taking as axiomatic
that something is real, we must speculate on the possibility
of vat builders, who would not be bodies in a vat themselves,
and must have a "normal" reality. Doing so gets back to the
possibility of the finite or infinite regress of a couple of
paragraphs ago, but it gives us at least someone for which
reality is real. It doesn't seem all that interesting to try
to decide if that someone is us, or our vat masters.
That, then, leaves us with the
possibility that the vats and our existence in them evolved as
matter evolved in the universe, without a builder, just
as life evolved with out a "designer". While I find the prospect
unlikely and ridiculous, it is also possible, and the only
interesting way to think about the question.
But what does that mean? Isn't the "vat" then just our bodies?
Back to square one. I thus find the question meaningless. Or,
I find it to be "yes", we are brains in a vat, that vat is our
bodies, and yes, reality is "transformed" from physical reality
to perceived reality by various understood and non-understood
mechanisms. How the latter processes occur is a mystery,
at least in terms of the experience of qualia. (qualia
are the term for things like what makes the experience of "red"
look "red", and are discussed a bit more in
this blog entry,
and remain an unsolved problem).
The Matrix Reloaded
Ok, I'll try to be a good sport and look at this in terms of
the "science fiction scenario", i.e., a race of machines (or
whatever), built these vats, and put our bodies in them, and
our experience of reality is not real at all, but a simulation
run by the machines and input to our brains (i.e., The
Matrix again; it does a better job of looking at the issue
than I ever will).
There are reasons to doubt the viability of such a scenario,
and these come from information theory and complexity theory.
When debating whether the universe is deterministic
or not (that is, if we know all the physical laws of the
universe, and the state of all its constituents, then is it
possible to calculate any future or past state?), it is pointed
out that the problem is too complex, that is, it would take longer
than the age of the universe, with a machine larger and more
complex than the universe, to do the calculations. I'm not sure
that this has been proved or not, but I believe it
has been (well, that's rigorous, isn't it?). Thus, a machine to
run the simulations to our brains is likely too complex, and
thus unlikely to exist. One can posit the universe itself as
such a machine, but doing so simply gets us back to some of the
points made earlier.
One can think of the problem in terms of agency. This
may be the most interesting way to do so, as the differences are
meaningful. When most people think of reality and our place in
it, they think of ourselves as agents in the world, doing this
and that. In the brain in the vat scenario, however, there is
no actual agency; we are simply spoon-fed an apparent reality, and
all presumed agency is an illusion.
Evidence of agency would be my actions having an effect in the
real world. If I flap my arms like the proverbial butterfly,
and the proverbial hurricane occurs in three months, then I have
agency. A more interesting way to look at agency is in terms
of gravity. All objects with mass have a gravitational effect
on all other objects with mass throughout the universe,
eventually. If I walk across the room and throw a baseball
out the window, my mass walking across the room, the mass of
the moving baseball, etc., has a gravitational effect on
everything eventually. While the effect is minute,
it changes reality in some way, somewhere (and,
forgetting gravity, the baseball may hit my neighbor's car,
changing my reality more quickly). If there is no actual
agency here, and all such things like this are simulated by
this putative machine, then we are back to the information
theory paragraph, so it appears that looking at things in
terms of agency doesn't get us any closer.
I've been trying to think of this in terms of consciousness
vs simulated stimuli inputs, but such is beyond the scope of
the question. Clearly it is the latter, as we are given the
problem of a brain in a vat, and we assume consciousness lives
there (at least for this question).
No Revolutions or Revelations
So, I find the question meaningless, and the prospect of
a brain in a vat extremely unlikely if not impossible in any
case (due to the limits of physics and information theory),
and certainly no evidence to support the notion, and thus
Occam's Razor again asks us to accept the simplest explanation,
and that is reality at face value. (Such brain in the vat
evidence might be "glitches" in the simulation, such as deja vu
was in The Matrix).
Well, I think this was my worst effort of the three so far.
As for the last question on gay sex, even tho we came to the same
conclusion, I'm disappointed that the Prof didn't take the social
relativism angle. He has morality out there axiomatically and
demonstrates how gay sex is not contrary to that morality, but
does not anchor the basis of that morality (indications are,
however, that will come later in the book). I think the approach
he uses is vulnerable to further attacks and line crossing via the
social relativism angle, quite frankly, but who am I to question?
In any case, I like my angle of positing East Pole style thought
as an explanation for appearances of common shared reality and
virtue that is illusionary absolutism. It solves alot of questions
cleanly, IMHO, yet it is, in and of itself, a scary result, as
all relativistic answers are. I give myself an A on the philosophy,
and a B- on the writing on Question 2.