Introduction
Sénèque was interested in the ephemeral nature of life and therefore of the existence of a human being [1]. He set out to find out how to give meaning to this existence only in the context of this brevity.
We can extend this quest by questioning the sustainability of humanity.
History and duration of humanity
There is debate about what should be considered the beginning of humanity, should we place it at the first hominids, a few million years ago at the emergence of sapiens, a few hundred thousand years ago or at the beginning of what is considered to be the historical era, about 5000 years before our era.
Shouldn’t we also consider the origin of the emergence of life on Earth, a few billion years ago, since, according to the Darwinian schema, we would have come from it through mutations and evolution?
By extension, we arrive at what is called « the origin of the universe »[2], since it is from its constituents that we are made.
At this stage, the definition of time must itself be redefined because, if in one model it is attributed 13.7 billion years, which is only 3 times the age attributed to the Earth, in another frame of reference, our current time, this origin is rejected to infinity from our past.
If we consider evolution, as far as humanity is concerned, we can say that it has an « exponential » type of appearance and that the inflection point of this evolution towards modern humans (today) really began in prehistory, a few tens of thousands of years ago [3].
Of course, the caveman did not have our knowledge of the world, but it is probable that his intellectual development was not very far from ours. In other words, transplanted to our time, it could probably have adapted to it.
As a witness to this exponential evolution of knowledge, it should be remembered that today we have more living scientists than there were in all our past.
So for the future, we can start from the state of things today.
The future of humanity on a cosmological scale
The sun
A first observation is that the resources that allow us to live are already well underway.
If the lifespan of a star like the Sun is 8 to 10 billion years, we are halfway there. The danger is not at this time, because in its evolution the heat of the Sun increases slowly but steadily and it is estimated that in 500 million years the increase will be such that plants will disappear on Earth.
The solar system
Another threat is that the solar system follows a chaotic law, and if its short-term stability is not too compromised on the scale of 100 million years, nothing can be predicted.
Even a slight change in the Earth’s orbit would have consequences that are difficult to predict. Similarly, the passage of massive wandering bodies (wandering stars, for example) near the solar system would be likely to destabilize it.
Meteorites
It is difficult to predict that we are safe from a cataclysm, but the examination of the past has shown, through the extinction of the dinosaurs, that this could have important consequences. But a disaster of this magnitude is quite rare.
All this means that many threats, beyond our control, lie in wait for us.
The human
But this is not the worst because, without a doubt, the most to be feared are the ecological damage resulting from uncontrolled human activity, which has effects that can make the planet uninhabitable, in the relatively short term (less than a century), not to mention the wars that will not fail to occur when resources become more repletive. This inventory is, unfortunately, not exhaustive and the existence of humanity could well turn out to be a parenthesis, an incident, totally negligible in the context of the universe.
Humanity will face a very dark future where its survival is likely to be greatly compromised.
Regarding long-term threats (beyond a million years), it is not inconceivable that a migration of part of humanity to planets or satellites of more distant planets could offer a respite, provided that it reaches that point.
The End of the Universe
The universe, itself, as space-time, has no chronological character, it has no past, no present, no future: it exists. It must be remembered that the concepts of past, present, future, time and space that we have used refer to the human being on his line of universe, included in space-time, not to the universe which needs nothing but itself to exist: he necessarily exists because as a part of him we are there to see it.
These notions of past, present, future, time, space on our line of universe oriented by our own time, result from an internal layering, of the mathematical object (a manifold) representing the universe-space-time.
Humanity must think of existence in its precariousness
In the philosophical approaches that we have presented, that humanity has developed, essentialist, existentialist and religious, we have thought of it in the present as an observation of our consciousness, without integrating its precariousness, which is nevertheless an essential characteristic.
We must certainly reconsider our existence by integrating this dimension of humanity’s precariousness on a cosmological scale. Given that we are cosmological objects in our constitution, this is natural. What consequences will this have on the analysis we have made?
We must reconsider our existence by integrating this dimension of humanity’s precariousness on a cosmological scale. Given that we are cosmological objects by our constitution, this is natural.
Representation in space-time of our existence
General relativity being a theory that defines and describes the universe as a space-time, our existence is located as an « island » in this space-time that must be located in this space-time and also define its spatio-temporal parameters.
We are faced with a first difficulty, because if it is easy to delimit the contours (spatio-temporal – their extension in space and time in Newtonian language) of our material region (the atoms that constitute us, located mainly on Earth at the moment), for our mind it is different.
Indeed, the capacity of our mind to apprehend the universe with a knowledge which, if it diminishes with distance, progresses according to time and associated discoveries and theories.
Since it is difficult to associate a boundary with knowledge, an open-type geometric structure, giving an order of magnitude, will be better suited to the description of its extension. This extension is obviously constrained by the (supposed) limits of space-time representing the universe.
It is therefore necessary to make a double representation for humans, one for the physical part and the other for one’s understanding. It can be two connected regions of space-time or more simply the material part included in the part associated with the mind that contains it.
See figure below. Other « intelligent species » in the universe, which may exist in other islands of space-time, are not represented.
Development of humanity: contingency or finality?
The history of our advent as the dominant species on Earth suggests that it was rather a contingency, a coincidence, that allowed our advent. Dinosaurs had reigned for several hundred million years, when the gigantism, and their associated gigantic food needs, for example, which had set in, was fatal to them.
A cataclysm would lead to their disappearance, while small mammals, with much less needs, survived and were able to develop.
On the other hand, a state of development of a species, which cannot survive catastrophic hazards that are unavoidable in our universe, must be considered unsustainable. As such, small mammals were more viable than dinosaurs.
Will their evolution, up to humans, retain this attribute?
The way we can look at our society at the moment leaves us doubtful. Humans have modified the natural context of our planet to adapt it to their needs.
Until the industrial era, the Earth tolerated it well, but nowadays we are aware, at least some of us, that if the pace of change in needs does not slow down, we will be heading for a major ecological disaster whose consequences will be dramatic to the point of making the Earth uninhabitable in the short term [4].
That wisdom prevails over madness is far from certain, but here, at least, unlike astrophysical or cosmological events, we are the ones who have the keys to the success of this smooth ecological transition, allowing humanity to be preserved in the short term.
Is the finitude of civilizations a structural property in cosmology?
We can indeed ask ourselves this question. The finiteness of humanity in time and space is an observation for our mind, in a Newtonian-type approach where time and space are fundamental concepts.
But within the framework of a space-time, humanity exists, because as a part of space-time, which has neither past, nor present nor future (in the Newtonian sense), it inherits the property of existence of the universe without past, present and future.
We can see the difference with the Newtonian approach where, before the advent of humanity, it does not exist and after the end of humanity it no longer exists.
Necessity of a consciousness for the existence of the universe?
This point, of a possible necessity of a consciousness in a universe, to attest to its existence, has been discussed in other pages of this site. The idea is that we ask ourselves if a universe that would not have consciousness to note its existence exists.
This is assumed in a general way, by postulating that it is not the fact of existing for someone or not that is concerned, but the fact that there must be at least someone to establish existence for existence to be possible.
A universe without consciousness does not exist, this being stipulated, in a restrictive way, in the framework of a representation by a space-time.
Transcender la finitude?
Can we attribute an intrinsic value to something that would be part of the ephemeral? Mathematics, art, for example, can indeed satisfy this type of criterion. For mathematics, we have already emphasized the « transcendental » character of this discipline, which allows us to go beyond our conceptual limits. In art, for example, one can find incomprehensible works, which nevertheless will exhibit value, solely on the form of their expression, by the impressions and sensations they inspire.
This would tend to show that something limited can have a value that transcends its finitude.
To be continued.
[1] « De Brevitate Vitae », Sénèque, around 49 AD. He proposes to accept its ephemeral character, which he observes, and to devote himself to a human fulfillment, through his action according to values which, at the time, seemed essential to him, for example political and moral, which is subjective, for the good of the « city » and its occupants. Apart from believers, for whom life is a test to deserve eternal life (paradise), philosophers have sought a method involving only life itself, in its ephemeral character, in an attempt to give it meaning and a reason for existing.
Later, in a more elaborate way, the philosopher Friedrich Nietzsche, to name but one, proposed a method, « the great style » feeding on the antagonisms proper to life without hierarchy between them that he describes in « Beyond Good and Evil » and introducing the notion of « superman », also leading to a solution that involves only life, notwithstanding any reference to its ephemeral nature.
His sad end (he sank into madness) leaves us doubtful about the effectiveness of his attempt which, even if it is based on a very innovative analysis invoking psychoanalysis, did not allow him to achieve the serenity so sought after by philosophers. Moreover, the abusive interpretation of part of his philosophy (including the « superman ») by the Nazis gave the sad results we know.
It was useful to mention this because structurally, this philosophical approach that considers only life, without anything else, is in line with the modern approach invoking a space-time, which we describe in this text, which considers only this space-time, which contains all the properties in an « internal » way, without reference to anything external.
[2] This refers to the « Big Bang » in the Standard Cosmological Model. This term Big Bang is contested, (see James Peebles), in the context of a space-time universe, because it refers to the « creation » of the universe invoking Newtonian concepts of time and space. What we call the past of the universe is in fact our past on our line of universe oriented by our own time (see book « You Said Big Bang » by J. FRIC).
The universe itself, as space-time (a concept that encompasses time and space as appearances) has no past, present, or future, which are only internal elements of its geometry. It necessarily exists for a consciousness because it presupposes its existence in order to exist. This point has been discussed at length in other pages of the site.
[3] It should be noted that the reign of the dinosaurs, abruptly interrupted about 66 million years ago, had begun 300 million years ago. We can see how short our history, if we start even from 50,000 years before Jesus Christ, (prehistory), when things began to evolve (slowly), is. The inflection point of acceleration of evolution really started with the Mesopotamians, Babylonians, Egyptians, and then ancient Greeks who really brought us into the modern era.
Before, between the first hominids and prehistory, the situation had hardly changed (different variants have been found in different parts of the world, but at a stage of development that remained very close to that of apes).
[4] There are milestones to be crossed, because demographic predictions predict that the Earth’s population will have decreased by 2100, which « mechanically » reduces pollution. Until 2100, at no time, should an increase of 3°C be exceeded. These climatic phenomena are non-linear and their divergence is cataclysmic, as evidenced by the planet Venus, Earth’s twin sister where the surface temperature reaches several hundred degrees Celsius.