First the basic attacks
1) Daniel Dennett approach ‘when philosophers claim that zombies are conceivable, they invariably underestimate the task of conception (or imagination), and end up imagining something that violates their own definition’
To which they challenge Dennett to prove it
2) Kriple approach - reference and knowledge require us to be causally affected by what is known or referred to (Kripke 1972) if zombies are conceivable, so are epiphenomenalistic worlds. But by the causal theory of reference, epiphenomenalistic worlds are not conceivable; therefore zombies are not conceivable. (I will use something a bit similar later)
To which they reject the causal theory of reference (that’s a fairly decent bullet to bite)
3) What about science?
Most objects in the universe obey laws like entropy – but qualia seem to be able to be created or destroyed independent of a number of such laws. Why does this apply?
To which they respond that they are adding something like a simple ‘science doesn’t apply here’ rule.
4) Why are qualia at all consistent with reality.
A zombie philosopher might say ‘they aren’t’ but think of all the ways qualia could relate. Basically why does the physical world relate to quail in an even vaguely sensible way since it has no impact? Evolution can’t be driving it. Why not have 50 people sharing the same set of qualia as if they were a single person (since they can’t affect anything it presumably doesn’t cause problems to an ep zombie philosopher) or one person being 50 people (which is a bit more realistic maybe). Or for them to just have a totally different completely useless nature? It seems as if something designed qualia in order for them to be useful – a god? Remember we don’t have evolution or natural selection to fall back on here.
5) Being right by being wrong
broodsphilosophy has a argument based on how Epiphenomenalists need to be wrong to be right.
epiphenomenalist-zombie... while thinking that the physicalist is right, still argues and discusses that this assumed entity, while not affecting the behavior, is still there as separate somehow... we can say that the theoretical abilities in the epiphenomenalist-zombies don’t function quite as “they are supposed to”. But by some strange miracle this “not functioning as supposed to” of the abilities PLUS the fact that in the actual world there happen to be psycho-physical laws, end up with the behavior of epiphenomenalist philosophers (which btw can be explained same as the zombie-epiphenomenalist behavior) producing and being inline with their phenomenal beliefs, and being true (we are working within epiphenomenalism view). This leads us to
6) Zombie semantics
Imagine zombie chalmers (pro zombie) and zombie Dennet (anti zombie) arguing about the existence of zombies. what does zombie chalmers mean when he talks about a zombie?
Presumably the argument for conceivability collapses. However now we could just say 'zombie mean nothing because they don’t have qualia (as distinct from what a physicalist might mean by qualia). But this defensive position doesn’t solve all the issues.
But for one this takes the form of the old religious argument
“if god doesn’t exist morality doesn’t exist’
The moral atheist argues something like ‘morality is valuable without god’ So it isn’t new or widely accepted as proof
And two, the Dennet and Chalmers both describe the same thing from the same experiences and infer meaning to be something from that. Effectively Dennet infers that the physical world is more and Chalmers infers it is less and that there is an additional realm that makes up for that ‘less’. In the zombie example there is no real conciousness+ the hypothetical double zombies are debating is nothing anyway.
7) Zombie justification
Since our zombie twins, in contrast, have no experiences, their quasi-phenomenal judgments are unjustified. Chalmers suggests that even if qualia have no causal influence on our judgments, their mere presence in the appropriate physical context partially constitutes the contents of the thoughts involved: it ensures that our thoughts are about those qualia.
Is this true? This appears to be like saying that if there is a duplicate of you on mars talking about a tree, and you are talking about a tree, you are talking about the tree on mars even if you are mistaken and there is no tree in front of you.
8) opening the door to more problems
What is the nature of qualia? If we state that it doesn’t obey natural laws what laws do they obey? Ideally can these be documented? What would such a documentation look like?
this of course brings us to
occams razor arguments against zombie philosophy. Note that Occam’s razor is often misunderstood, however it appears to apply here.
9) why are qualia seem to be so poorly developed as a model.
there are lots of thought experiments seldom done to elaborate on the model - what would happen if you took a trip to zombie world - what if you came back again? what would it be like? what if you steeped halfway into zombie world? what does the answers to that say about the relationship between qualia and matter? What is the just of the rule that attaches qualia to matter? If we have billions of examples in the world why not specify it a bit more?
10) The nature of possible worlds and Occams razor
I propose that if qualia are something that can be duplicated in possible worlds they are part of the world. so saying they are inaccessible to science is not to say there is a bridging law but instead to say there is a series of ‘exception laws’, e.g. entropy doesn’t apply to qualia, sped of light doesn’t apply, cause and effect laws don’t apply etc etc - quite complex. Normally an Epiphenomenalist can say ‘hey I’m just adding one bridging law to explain one additional fact - I’m suggesting they actually need to almost exactly double the number of laws in the universe to apply to qualia and to other stuff or they are messing with the very model of conceptual worlds.
Most ep philosophers are happy to accept qualia as ‘in this world’ so what they really have done is just sloppily described what they are doing as something more simple than it is.
11) What is ‘you’ or ‘me’
if you dump causality as important for connecting qualia with eachother or yu with the physical world you raise issues regarding your own continuality – if someone recreates some pattern that happens to trigger the same qualia somewhere else is that all of a sudden ‘you’? That seems to open interesting doors to a new form of quantum immortality with even wider reaching possibilities in fact one can ask the question why other sections of space aren’t triggering your qualia right now.. or are they?
12) Believing Illogically
If you are other than 100% clear about epiphenomenalism but you care about the truth value of your statements (at all) then you get Richards
argument for free will - you can make yourself right by rejecting it but can’t make yourself wrong by rejecting it and you can’t change anything if it is true.
To explain - because the data for decision making is on the qualia side but the encoding of the conclusion is on the brain side (and on the computer in front of you). the inability for qualia to inform the brain is fatal to having a logical chain of causality.
Or as a set of statements
1) there is no such thing as 'I am a zombie' so 'I am qualia'.
2) Qualia cant effect the physical world (this is ep philosophy)
3) from 1 and 2 - I can't effect the physical world
4) beliefs (as in a logical structure of beliefs) exist in the physical world (stated and also implied by the fact that they can be written down etc)
So
4)a) if 2 (ep philosophy) is true then I am either a believer or a non believer as a result of the physical facts - I (qualia) can't change it.
b) if it is NOT true then I am either currently a believer that it is true or not true and I should if I believe in truth, try to change to not believing it.
Counter – why not have a soul containing the qualia and having it’s independant beliefs?
First for background consider
eliezers Cartesian theater argument to represent scientific psychology’s position. We seem to be able to separate out most ordered thought / internal dialog as ‘not us’ a sort of process we just happen to observe not actually duplicated in the qualia shadow.
Now with this in mind, I Question the effectiveness of the potential for effective connections between Qualia that would allow us to hold complex beliefs beyond the physical world in ep zombie philosophy - because if zombies act entirely like I do then the precursors for my thought process are almost fully explained by my brain patterns. It would be hard to have a experience of anything other than a completely minimal nature without being blown off tack by them - a concept like well developed epiphenomenalism independent of the zombie strata should be well beyond you. Potentially ‘green’ might also be given enough understanding.* (more explanation at the end)
In the best case scenario - you can imagine we have a 'zombie me' writing about not believing in zombie philosophy and a 'real me' writing about not believing in zombie philosophy but screaming out inside that he does believe in it, a recipe for insanity I suppose (although as I suggested earlier I don't think this scenario is plausible because you would be blown off track). On the other hand I know that isn't the case, you'll just have to take my word for it unless you are also a non zombie philosopher. Actually one would expect it would apply to a lot of logic - no reason for it only to apply directly to qualia which begs the question as to what range of logic the zombie philosophers think this applies to.
Good news is most ep philosophers don’t seem to believe in this.
13) Defensiveness
The argument for ep zombies is extremely defensive, it proposes something that is experimentally impossible to disprove and uses concepts like ‘conceivability, and places the burden of proof on the other side (to prove they are not conceivable). This isn’t proof that it is a bad idea, (unlike possibly some of the above) but it invites questions as to why it is defensive even beyond the point that it needs to be (i.e. one can still be a dualist without rejecting any connection at all with qualia). Even the original argument itself about the conceivability of zombies seems to beg the question regarding whether physicalism is false so the debate apears to exist largely in the 'zombie world'.