harvey1 wrote:I didn't say I would write something nasty to you...!
I was speaking hypothetically :-)
Any way, in principle are you suggesting that our thoughts and actions today were probablistically predetermined at birth just like any physical phenomena? For example, we have a pretty good idea that Halley's comet will probably be close to earth in 2061. Are you saying that in theory we can predict what someone will probably be thinking in 2061 if we had a similar level of understanding of the world that we have in order to calculate Halley's next pass?
Honestly, I'm not sure, and I don't think it matters much. I suppose that it might be possible in principle; however, comet orbits are vastly less complex than brains, and thus it would take an enormous amount of knowledge to predict human behavior (as compared to the amount of knowledge required to predict comet orbits). Furthermore, our brains are affected by our environment; depending on the desired degree of accuracy of your prediction, you might have to simulate the brains of everybody on the planet, which is not really feasible (at least, not until the magical wondorous Singularity comes along, heh). This is why I'm saying that, in practice, the question whether or not our thoughts are predetermined doesn't really tell us much.
That is, decisions are entirely the result of a causal chain of chemico-physical events. Saying that we are not in principle the decision makers of many of our decisions seems to me to be contrary to our experience, including our collective scientific experience.
I don't think you fully appreciate the materialsm-ness of my position. I think that we, ourselves, are "a causal chain of chemico-physical events". All we are is chemicals in motion; there is no decision-making part of us that's separate from these chemicals. From the scientific standpoint, this crude model of humans makes a lot of sense, because it explains the effects of brain damage on personality; the results of MRI scans, the recently invented
remote control for humans, etc. -- as well as the entire field of neuropsychology (or cognitive science or whatever it's called). Dualism has trouble explaining things like this, because it relies on having separate mental entities for everything.
In my opinion, the chief problem with your epiphenomenalism is that the mental aspects of our physical experience (which is considerable!) would have no other biological purpose than to provide a selective advantage for our species.
Firstly, this is not a problem -- on the contrary ! It makes very good evolutionary sense for a species to have the capability for abstract thought, because this allows an individual to build up mental models of the world, and to predict what would happen, almost in real-time -- as opposed to waiting for his children and grandchildren to evolve proper behaviors.
Secondly, as Carl Sagan points out, natural selection does not select the objectively best traits; it just selects the ones that are good enough for the environment. Thus, some traits that provide evolutionary advanatges can have weird side effects -- such as moths who fly into candle flames due to their simple navigation systems (based on light sources); sickle-cell anemia (the mild form of which protects against malaria); the human appendix (it's not harmful enough to disappear); and, according to Sagan, the human tendency to develop religions (an artifact of our very useful pattern-matching mechanisms).
So, on the one hand, our capacity for abstract thought has a massive evolutionary advantage; on the other hand, it may have some side-effects, but they are either neutral, or not harmful enough to make a difference; thus, I disagree with you when you say:
As long as the mumble-jumbo thoughts have no effect on our survival as a species, there's no reason that nature would have gone so far out of the way in constructing an illusion of free will and mental constructs which appear to causally change the world.
Come to think of it, what do you mean by "mental constructs which appear to causally change the world" ? I certainly have no illusions of changing the world by will alone, though I suppose some Wiccans might.
It is a commonsense realism including such basic mental thoughts such as we live on a planet, there is water on this planet, etc., etc..
Yes, it's common sense, but that doesn't make it
necessarily true. For example, we could all be living in the Matrix, or zoned out on nano-drugs, and all these planets could be nothing more than elaborate illusions. True, the probability of this actually being the case is vanishingly small, but it's still possible.
Putting this in epiphenomenalistic language, there was an evolutionary advantage in us having a mental construct of the world where we believe that our thoughts led to causally bringing about a dam, but we must realize that the mental thoughts did not really causally bring them about.
Right -- we didn't just will the dam into being, we built it out of rocks and such. It's rocks that are ultimately important, not thoughts.
but then we are forced to give up the thoughts as the real reason that a dam now exists there.
I'm not sure what you mean by "the real reason"... As I see it, the real reason the dam exists is that someone went out and physically moved the rocks.
Bugmaster wrote:It's nice to be able to use a metaphor for describing the processes that go on in our brains, as a shorthand; i.e., you don't say, "the following chemicals in the following parts of my brain combine to blah blah", you say, "I think I like apples". However, the notion of thought and consciousness is just that -- a shorthand, or a model (and a pretty shaky one at that) of the physical events that are going on.
As I think I showed above, this leads to absurdity and therefore must be rejected.
As I think I have shown above, this is false :-) Having shaky models is already much, much better than having no models at all. Quantum physics is not required in order to build a dam; Aristotelean mechanics would suffice. And the power to build dams, and other custom artificial structures, is a clear evolutionary advantage, so it makes sense that we'd eventually develop the capacity for it.
I think every conscious thought, every intention, etc., has a scientific reason.
I still don't see how this can be, since you've moved your dualistic entities -- the "mental properties" you refer to -- beyound the realm of science, which can only study the physical. You can claim that our thouhgts, etc. have some sort of reasons, but I don't think you can claim that these reasons are scientific.
...there is no such physical law that makes me think that I ought to eat lunch. There might be, and almost undoubtedly are, non-strict laws that my brain senses a feeling of hunger, but there is no strict law that requires that I think that I must eat right now.
I suppose that's true, but the hungrier you are, the higher the probability that you'll decide to eat... right ?
The problem with materialists is that they are duped by this distinction. They assume that an efficient cause is also the final cause, and in this way they end up coming up with absurdities such as mental properties do not actually exist.
I think I have shown quite clearly why I think that mental properties do not exist. And I am still not seeing how you explain the fact that changes to our physical bodies (especially brains) affect our mental states -- and vice versa. I understand that you are postulating a logical reason that necessitates this, but I don't think it's parsimonious.
This is where pragmatic factors come into play, and ultimately I think pragmatic factors are dominant.
Ah, can you give me an example of a pragmatic factor ? I'm not sure what they are.
Anyway, sorry if this response was rushed; I'm strapped for time at the moment. I'll respond to your other posts tomorrow, hopefully.