I propose that the mind is a material substance which organises the components of the body. Mind and body have different functions, but they are not seperate. Thoughts and ideas, on the other hand, are the immaterial results of the material mind, but they are not, as Descartes may have believed the mind itself.
Neuroscience, in seeking to explain the physical functioning of mind, does not disprove the existence of the soul, it seeks to explain how the material mind is capable of creating the immaterial (thoughts and ideas). Material substance is at the origin of the immaterial (Read Vishnu Purana, Genesis, the Big Bang Theory...) But the inverse is also true.
Thoughts and ideas, through action (dynamics) are manifested into material reality. These actions constitute our individual nature (our soul!), and create our karma. Karma is a system of causality in which every action has a cause and an effect.
To respond to your terms: The soul is the collection of memory, desires, beliefs, and character traits which can be altered by altering the physical brain. A simple consciousness can have no attached beliefs and be the reactive mind of a sea turtle swimming peacefully in the sea, but consciousness exists through thoughts and perceptions, even in a sea turtle. The difference here, and the reason why human consciousness is "honourable" as suggested below, is due to the human capacity for moral choice. Life (the flux and flow between immaterial and material) is sacred because it is the vehicle which allows the soul to reunite with the everlasting and resolve the dualistic objections you have raised.
1. The soul exists as the immaterial manifestation of our material existence. Its qualities are present in our thoughts and in our actions.
2. The soul continues to exist after our death in causality (karma).
3. The soul may seek enlightenment as a means of arresting the cycle of karma and rejoin its origin, the eternal soul which has created all of existence.
If this is the case, we have two more problems, (1) this doesn't seem like very much of a thing for a soul to be.
This would depend on one's spiritual progress, no? Must the soul be complex to be the opposite of "not very much of a thing"?
(2) this attempts to answer the question "how do I experience things?" with an homonculus, that is to say, by positing an experiencing entity and declaring the problem solved. The problem with that is that we already are experiencing entities, and we don't get any closer to figuring out how conscious experience occurs by suggesting that an experiencing entity exists in our brain to have conscious experiences.
It took me a while to un-tangled this concept, so forgive me if I restate your premise to be sure that we agree: Is consciousness intrinsic to our conscious experience?
A further, though less convincing objection is as follows:
(3) Dualism violates the closed causality of the material world by introducing immaterial<->material causality and immaterial->immaterial causality. According to Ockham's razor, we should not accept these two additional forms of causality without good reason to suppose that we cannot explain mental phenomena without them. Thus, if a substance monist account of the mind adequately explains mental phenomena, it is more desireable than the dualist account.
We must accept this duality, as well as its monist counterpart, in order to understand this mental phenomena. The one begets the other and forms a whole.
All that said, soul theory (and dualism) are really the only way for reincarnation to be possible it would seem. The fact that millions of people believe in reincarnation lends no strength to its reality - appeal to the masses is an argumentative fallacy.
I entirely agree with your statement concerning appeal to the masses as an argumentative fallacy. But one may argue that conscious awareness determines the experience and therefore for each individual, that which he believes is necessarily true. Which is true: a single concept supported by a single self-awareness, or a universal truth as experienced by a given "mass"
All this seems patently absurd.
Other issues with reincarnation
Someone else has already mentioned this, but why are there more humans now than ever before? Significantly more!
What exactly carries over from previous incarnations? Memories supposedly are, though they are "suppressed" until drawn out by meditation, hypnosis, or quackery. What about morality and personality traits? This seems harder to verify, but at least in the case of morality, the effects of similar moralities ought to be visible in the successive generations of humans. For example, a human with good karma ought to reincarnate as a human of higher standing. Are all humans of highest standing accumulating good karma? If not, then morality doesn't seem to carry over between incarnations (or maybe it too is "suppressed") which seems a rather difficult and absurd moral code (constantly trying to make up for the unknown sins of a past life while trying not to overburden your future self, both of whom may be very different from your current self) or humans of high standing simply aren't reincarnated from decent humans of lower standing.
It strikes me that you are judging the concept of karma against a different belief structure. Rather then argue against it philosophically you are attacking it as absurd without investigating the sources. Your arguments here seem to rely on the Western concept, or rather misunderstanding, or karma.
Consider the question on a collective scale:
Will the experience of my lifetime have an effect on the spiritual progress of a future generation? If you believe that a disrespect for nature or killing resulting from a struggle over natural resources will not have an effect on some future soul I would argue that you are mistaken.
As a conscious beings with moral choices to make we are responsible for the outcome. This is more akin to karma then your concept of moving up through a hierarchy based on individual merit.
It is not a valid arguemet to state that re-incarnation cannot exist because the population has increased. This suggests that a predetermined number of souls, with a specific shelf life exists and therefore precludes re-incarnation.
I admire your arguments, and hope that we can continue this thread until it has achieved its ultimate purpose...