The concept of life itself is pretty simple. You either experience life long enough to reproduce bringing further life in to this world with a similar genetic markup to your own. Or you don't. And eventually you die.
As time progresses this simple lifecycle becomes increasingly complex as life adapts to its surroundings and optimises its chances for survival and genetic reproduction. Not all life is optimised for direct reproduction (eusociality) which indicates the reproduction step is not a necessity in life, since the continued success of genetically similar kinship seemingly ticks this box.
The evolutionary process itself has some optimisations in it, such as genetic mutations that flare up every now and again to test the boundaries. Often these mutations are based on past successes, for example a chicken may grow additional legs instead of wings, and these mutations are often repetitive with known mutations appearing in life a known percentage of the time. This has some big advantages for when the world surrounding the reproductive life changes, allowing for adaptations to be continually tested in adapting environments and should the four legged walking chicken suddenly find itself in a world where its mutant feet are more useful than wings, and it increases its own chance of success in reproduction, eventually the world would be full of four legged chickens.
I can imagine in the primordial soup that this discovery of reproduction took some time, but when it took hold life flourished. Most life seems to have a desire for reproduction, even down to cells, bacteria, and viruses. This is simply explained by the fact that without reproduction, life wouldn't take hold and evolve. When thinking of the universe as a linear march through space time, a random reproductive organism that came about in a soup of non-reproductive organisms that managed to survive is therefor going to grow, with the reproductive ability now existing as a trait in the reproduced organisms.
As evolution becomes increasingly complex, the evolutionary output becomes something that is more capable of understanding the world around it, and more adapted to it. And herein lies the interesting part. Eventually, life will become completely optimised for the universe it finds itself in.
We as humans already have elements of this optimisation that came together in an evolutionary synchronous dance that allowed us to have complex societies, develop fire, complex tools, language, inhereted wisdom, which together created a new type of evolution, an artificial type called civilisation. Given a stable, nutrient rich, warm but not hot, wet, varied and protected planet life will evolve through the reproduction process in varied ways until a being that can stand above it all exists. This being would have no adaptive reason to come about without the complexity of a dynamic, rich, and diverse biological system already having taken place within the stable atmosphere of this protected planet.
Thus civilisation is an obvious milestone for life. It's something that's unlikely to be fundamentally unique, but it requires a unique set of parameters in the life itself that discovers this concept. Dexterity, communication, empathy, etc.
These unique parameters are simply optimal adaptations to any planet that is capable of hosting complex life that is eventually capable of discovering civilisation. The timeline to discovering civilisation may be different on different planets, and in some cases it may come with gotchas due to limitations in the environments themselves. These gotchas would limit that civilised species' ability to progress forward through the next milestones, specifically things like where we are today with interplanetory exploration which will eventually allow for an entirely new set of capabilities for life, but on the civilisation evolutionary scale, rather than through life.
As life becomes more optimally imagined for the universe it finds itself in, it will also become more genetically homogonous, since there is less of a need for variation if the optimal solution for birth through death has been found. Humans are a great example of this, being a highly genetically homogonous species. There are no major adaptation events for our species on the roadmap, and there is little more we can achieve evolutionarily speaking to improve our chances of success on this planet. It feels likely to me that the next major adaptation event will either be completely artificial (genetic manipulation), or due to artificial changes to our surroundings (leaving our solar system, or life arriving from outside in to our solar system).
So then, we have an evolutionary process contained in a linear spacetime process with the fundamental rules already laid out to optimise life for a certain outcome. Knowing the rules of the game will provide answers in discovering the meaning of the game. Once we understand where life is heading, it should be much easier to understand why it's heading there. Without knowing where we're heading, as is the state of where we are today, there is no way to interpret the meaning.
I'm pretty confident that with our current understanding of the universe, and our current ability to manipulate it to create computations and simulations, that we are capable of simulating this evolutionary process up to the point of civilisation existing. It is trivial to work backwards from where we are today like that. I'm also pretty confident we could find several models to work backwards from that would produce civilised species in a simulated universe, and all of these models could be applicable to the universe we are in. We could call this "world simulation", ie. focused on the evolutionary process on a planetary scale. This would already provide us with some much needed narrowing of our understanding of the meaning of life.
This world simulation would become practical for understanding our own genetic encoding and what we might want to manipulate within it to improve our life in this world. Chances are, we would already find some unexpected answers by doing this.
But the universe is young. Very, very, very, very young. Life is young too. Covering life up until this point, and maybe some small predictions that would help us manipulate our genetic encoding, is easy. Predicting the next major events, that's going to require a very big computer. And a lot of data.
We may never know the meaning of life. Humans, and earth, could be a temporal existence as there may be life out there that is already much older than life on Earth, and much more successful in working through the next major adaptation events. For all we know within more dense clusters of our galaxy may exist a dense network of massively successful civilisations that are millions (maybe hundreds of millions, or even billions) of years ahead of our own, all pining for that more optimal next step in the evolutionary process and all pining for resource consumption on a scale that we are incapable of even imagining right now. If our understanding of life so far is applicable to this situation, then the resources our solar system provides could easily (and arguably correctly) be seen as more important than the preservation of our life by these already massively advanced civilisations.
But the meaning is out there. Waiting to be discovered. It may require some interpretation, and we may never get it exactly right, but by understanding this evolutionary path we find ourselves on and the direction it is heading, we can understand a massive amount about the meaning behind it.
Although it feels like we are walking through a forest taking whatever path of travel we like, the reality is that the universe, evolution, and civilisation are all on a predestined march. No matter what I do with my life, no matter what we do as a collective, on a long enough time scale the impact doesn't matter. Life will still find its way, because the direction of travel has already been laid out. The seeming randomisation and decisions we make are ultimately limited in impact, and limited in creativity, to what we are at that time, and what we know. The pyramids always would have happened because the structure is optimal and easy to discover at that time. Cars, computers, ships, rockets, roads, phones, electric cables, houses and flats, these are all obvious choices that although discovered and interpreted by humans, are fundamentally the most logical conclusions at that time, at that place, as a step in our civilisation's evolution. In any civilisation's evolution. You can't go to space without them.
Whether life can truly discover the path we're on is something that the universe already knows, and something for us to find out. Whether we can make it through the next adaptation event, and continually do so until the end of all time, will come down to luck more than anything else. There isn't much we can do about our position in the universe. There isn't much we can do to change the course we are on. A change in course outside of the universal adaptations would require us to not adapt at the pace laid out for us, thus limiting our position in the universe. That is the only control we have. Without knowing where we're heading, it's impossible to get to the destination any faster than by following the straight path laid out in front of us. We are walking alone in the dark with no map or compass, after all, with only dim lighting laid out behind us on the path we have already walked down.
Otherwise, we are simply discovering, and building discoveries on top of discoveries, and utilising these discoveries at the appropriate time. If a discovery should come very early through some fluke, then without an immediate use case our understanding of that discovery will be treated as a novelty until its role in civilisation brings about a need to utilise it. This is evolutionarily true as well. Rediscovery of important concepts may happen many times long after the initial discovery, due to the fact that the initial discovery wasn't applicable at the time it was made. There is a synergistic requirement to our discoveries as a civilisation in order for them to become permanent residents in our lives. This is much the same as natural evolution. And it's this synergistic requirement that dictates the linear march of nature and civilisation.
The linear path we are on is the purpose of life, it's why we are here. The universe has been laid out with rules that create this linear march of discovery and evolution. The universe has been laid out so that discoveries must be applicable in synergy to the environment they are born in to. There is a minimum amount of previous evolution and discovery that is necessary for the next change to be applicable.
