For me the only rational position to take is...Life is for living, live it and let death look after itself.
I agree here.
I'd say it's better to live as though you are only here once so make them most if it.
The argument does have elements of Occam’s Razor, or the theory of least assumptions - for unknowns we can use reason to attempt to obtain a more justifiable explanation.
I've found a good website which gives a good breakdown of the main arguments against these concepts (saves me typing for the next half an hour!).
"The Argument from Brain Damage, Impairment and Structure.
Phineas Cage is usually the best example of this argument. Cage was a 19th century railroad worker who survived a large iron rod that destroyed his left frontal lobe. Long story short: his personality changed due to the absence of his left frontal lobe. Then there’s this interesting case outlined in a 2002 article at New Scientist.
A cancerous brain tumor led one man to exhibit abnormal sexual tendencies — even pedophilia. Then there’s the murderer’s brain. A cyst growth in the right hemisphere of the brain almost led a child to murder another child! Then there’s the brain structure of psychopaths — one that exhibits structural abnormalities.
Then there’s the brain structure of pathological liars. Clearly, the mind isn’t separate from the brain and is therefore, not separate from the body. Think of what the dualist is actually saying: they’re saying that autism, down syndrome, MR, genetic disorder, neurodegeneration and the like are all the result of damaged minds that existed prior to the body or are the result of damaged minds due to the rearrangement of matter — even before birth! Couple that with the fact that some dualists believe in a benevolent god and there’s a clear conundrum!
Argument from Biological Development:
This argument is far simpler from the above argument. It states that since we begin to exist as material beings and since nothing immaterial is added during development, we are wholly material beings once fully developed.
Argument from Neuroimaging:
Ironically, this is also an argument against libertarian free will. Some of our decisions can be detected 10 seconds prior to the actual decision via monitoring of brain activity. A good question can be raised here: if the mind is an immaterial substance, how can it be observed and its actions predicted via material means?
Argument from Simplicity:
This basically narrow’s down to Occam’s Razor. Why create a distinction when both can be explained in terms of one? Why offer an extra step or postulate an extra entity when it isn’t necessary? Therefore, the simplest explanation is to be preferred: the mind is dependent on the brain and the mind exists via the brain and thus isn’t a separate entity from the brain and body.
As materialism is related to naturalism, dualism is related to supernaturalism. A Christian who is a dualist would conclude that god is a mind that exists separate from a material body. Therefore, we must know how to dispel such a claim and we must be equipped with the best arguments to refute such a claim. On materialism and thus on naturalism, the mind cannot exist independently from the brain. Think of the implications: not only does that make the common notions of god impossible, but it also implies the impossibility of the common notions of the afterlife. Whether the afterlife consists of souls or bodiless minds or whether the afterlife consists of minds that receive new bodies, the distinctiveness of the mind is a must in order for both to be possible. Unfortunately, the mind is not distinct; therefore, the common afterlife concepts are also disproved."
