Immortality is a notion that was common throughout various cultures from early days of humanity. The ancient Egyptians, the Jews, the Christian, the Muslim, the Buddhist, all hold (or held) in that or another form the belief the human soul is immortal.
The origin of that belief is almost obviously one of the most fundamental aspects of human psychology: the fear of death. This, combined the tendency to replace reality by wishful thinking, a treat acknowledged already by Sigmund Freud (and probably much earlier as well), lead to the invention of the immortal human soul. Whether immortality was achieved through reincarnation or ascent (descent) to Heaven (Hell), it was ensured or at least achievable (in the Egyptian superstition and the reincarnation doctrines, immortality is sometimes not guaranteed to less worthy persons; this in contrast to, say, Christianity where immortality is assured even for the worst of sinners, even though they might prefer obliteration to an eternity of torture).
One peculiar feature of immortality in most cultures is that either the availability of immortality or the level of comfort of the resulting eternal existence is strongly related to the extent the person deserves it. In other words, it is related to the extent she adheres to the principles and commandments of the given doctrine. Another interesting feature is the introduction of the immortal soul: it is common knowledge the human body decays and vanishes after death, becoming absolutely inert immediately at its occurence. Therefore immortality requires the introduction of a hypothetical invisible essence commonly know as the "soul". The physical body of the person is thus lost at death, but the soul which contains the mind of the person, his personality and consciousness remains, and that's what really counts.
So, to which extent can we, in this modern age of science and objectivity adhere to these ancient beliefs? On the surface they are no more than superstitions and products of wishful thinking and are therefore to be disregarded offhand. In this essay we attempt to address this question through a specific theory of immortality we suggest. This theory is drastically different from traditional beliefs and supersitions, devoid of any artificially postulated constructs and, in our view, deserves attention due to its natural philosophical foundation.
The question of immortality is directly related to the fundamental question of existence which occupied philosophers throughout time. What is existence? What is reality? Is there difference between objective and subjective reality? We make the following assumptions regarding those questions:
1. Reality is indeed there in some very fundamental sense, in contrary to what the solipsist might believe. There is no way to truly prove this assumption, therefore it has to be taken as an axiom. The necessity of axioms is somewhat reminiscent of the demand of religious doctrines to take certain things on faith. The fundamental difference, though, is that we adhere to "taking on faith" either things we're not really sure about (and then it's a mere "hypothesis") or such that really "feel obvious" like the consistency of the natural numbers; not things like "Jesus was the son of a virgin and a dove" which are far from being completely obvious (not mentioning absurd for any sober person). Neither Newtonian mechanics nor Einstein's theory of relativity are anywhere close to "obvious" in this sense, even though we do believe them to be good approximations in their respectful domains of application (for complicated reasons). The presence of reality is.
2. Reality is absolute, and therefore, no component of reality can exist out of the sensory reach of the self. In other words, it is impossible that only a fraction of reality is ultimately accesible to my sensors. Why do we say "my"? Because, and here we must agree with the solipsists, on the basic logical level only the existence of the self is ensured. The existence of the self is, to most opinions, an unquenchable axiom, or alternatively, a theorem by Rene Descartes ("I think therefore I am"). From the existence of the self we logically conclude the existence of all that is available to the sensors, using assumption 1: we know we can feel those things and we "believe" they are real. Here we postulate the opposite is also true: no thing is real which is not real by this claim. Otherwise reality would contain components completely disconnected from the self (the only thing existent on the "fundamental logical level") and the sense in which they "exist" becomes quite obscure.
3. Elegance is fundamental to nature. We know from a many century's experience in the study of nature, that it has one quality which is completely extraordinary and mystical: boundless elegance. The physical law which could have been expected to be chaotic and arbitrary turns out to take the form of a simple and beautiful set of fundamental principles. To date, Einstein's theory of relativity is considered the most striking example, though we think quantum mechanics and quantum field theory fall under the same category. Two extremes create the full effect: on the one hand, the simplicity of the underlying laws and on the other hand the breathtaking complexity of resulting phenomena. The beauty of the simple and the beauty of the complex are two things united in nature in perfect harmony, to much surprise. Moreover, studies in abstract mathematics, often guided purely by the pursuit of elegance always lead to the creation of notions ultimately paramount to the description of physical phenomena. This is an enigma nobody can explain but its overwhelming empirical presence and its syntony with intuition urges us to take it as yet another axiom (see Brian Greene's "The Elegant Universe" for some related information).
4. Existence doesn't depend on time on the fundamental level. The general theory of relativity teaches us space is to large extent inseparable from time and, therefore, claiming the past or the future doesn't exist is as solipsist as claiming other locations don't exist. It is probable one cannot even rigorously formulate a claim about the inexistence of other moments in time without the inexistence of other locations automatically following. Now, it might seem this assumption is already paramount to immortality, however, this is not the case, not for the sense in which we understand immortality in this essay. Immortality is to be understood as existence of an unbounded proper timeline, having an indispensable amount of "personal time" in which life continues, i.e. both mind activity such as thought and emotion and sensory experience is possible. Regarding this particular point it important to note modern cosmology based on the general theory of relativity violates the combination of assumptions 2 & 4, presenting many instances of the so-called "event horizons" through which information is barred from flowing and which therefore result in existent but sensory unreachable portions of spacetime. It is however known this view of reality is incomplete as it fails to explain in a satisfactory fashion phenomena such as the extraordinary homogeneity of the early universe. It is the hope of many scientists these issues will be eventually resolved by the ultimate quantum theory of gravity which is bound to exist and research aiming to discover which is ongoing. It is our hope this theory will eventually resolve the apparent contradiction.
Having laid out the assumptions, we are now ready to present the main body of the argument. As both space and time are inessential to the nature of existence, and as all of reality has to be within the sensory reach of the self, the self has to be able to experience, ultimately, all of the content of spacetime. Therefore, the timeline upon which this experience is located has to be unbounded on its own. Note that here we make the hidden assumption the universe as a whole is infinite. It might be claimed, though, that this follows from the assumption of elegance (see #3).
Okay, so our consciousness (as it is the consciousness which is relevant to assumption #2) is immortal due to abstract considerations, but what form does this immortality take? We all know the body rots and decays, so what allows this infinite continuation of the mind? The "soul" again?
We claim that the "soul" construct is both artificial and redundant. I.e. the nature of immortality can be understood by considerations which don't include any additional notion of an indestructible ghost or spirit. Imagine, in accord with the principle of elegance that the complexity and beautity of physical phenomena is going to grow indefinitely. Combine it with the view (which we adhere to) that the most essential property of life and intelligence is them being extremely high levels of complexity ("live" standing above "inert" and "intelligent life" above "unintelligent life"). Then it is inevitable intelligence and civilization (if not necessarily what we understand as human intelligence and civilization) will develop indefinitely. Upon such development, components of this rising complexity, which we shall therefore call "the spirit" (though it is in a way completely materialistic) will come to completely understand and "contain" things that inhabited the universe in the past. The spirit will, then, completely "devour" any information existent in those portions of the universe. This process is inevitable because assumption #4 ensures the past will always remain available to their (the spirit's) inquiry and because their development is in all respects unbounded. Therefore for each intelligent being a moment would come the spirit would "devour" it and it will become an inseparable part of some component of it (which may be thought of as an intelligent being on its own but might be much more than anything we could imagine using the notion today). This guarantees immortality in a way proof of failure, but in a highly unorthodox sense. Death is, in this view, similar to finishing reading a book about yourself by the "real you" who is actually a higher being from the distant future, a process after which the character forever remains a part of the being's "personality". Of course, the same fate awaits the being and so on and so forth ad infinitum.
Although in principle this theory promises equally eternal fate to everyone, there might be some sense in which it holds in it a sort of "karma". Namely, persons whose life was duller and of less constructive consequence might become more insignficant portions of the future "spirit". One must note, though, that in most respects this notion is completely different from the traditional one, for instance, it is completely
non-linear as it easily allows for multiple continuations for the same "individual" or merging of several "individuals" into a single one - or any other insane recombination you might imagine. No doubt many of the representatives of current religions would hold the notion fallacious or even heretic.