Ruminations on Selfishness.

Consider an animal in a resource-scarce environment. It makes a crude kind of sense to be selfish. The animal, presumably being stronger than other animals, takes the food it needs and mates with partners of the opposite sex without or without their cooperation and leaves more progeny than weaker animals.
However, this animal comes up against a problem if other animals, individually weaker than it, learn to cooperate. With force of numbers, they can fight off the selfish animal. They can cooperate to look after progeny and thereby, their progeny have a survival advantage over those of the more selfish animals. They form herds and prides and the purely selfish animals die out.
The herds/ prides grow into tribes as intelligence increases and we get a situation like the human animal which seems set to take over the entire planet and then perhaps starve to death as the resources are used up by uncontrolled population growth.
Humans are at a stage in evolution when they have clearly surpassed all other species in terms of aggression and technological development. Their aggression, presumably a remnant of the original selfish animal, is now directed towards other members of the same species, dividing into tribes referred to as 'nations' or 'religions'. Excellent examples of selfishness at this level are provided by Trump's 'America First', 'Brexit' in UK, 'Hindutva' in India and essentially all the 'Islamic States'. The idea being to divide humans into 'us' and 'them'.

This could go three ways.

1. We have sufficient weapons of mass destruction to make ourselves and most other animals and plants extinct. This would seem to be quite a likely option.
2. We could evolve further and learn to think of the entire ecosystem of the planet, control our population, distribute resources, find alternatives to polluting sources of energy, clean up the environment and develop a long term sustainable population of organisms on this planet.
3. Expand like a plague into the rest of the solar system and eventually into the rest of the galaxy.

The second option is so obvious that it may well explain the reason why we have not encountered aliens. It seems likely that life eventually finds an equilibrium as intelligent aliens learn to live with each other, control their own population and find ecological balance. This is the only option that would remain stable for long periods of time. There may be no reason to travel interstellar distances. Of course, it may also be that there is an interstellar civilisation out there with many kinds of life and intelligence and that they are waiting to see how we behave. Like naturalists observing animal behaviour in the wild without interfering with it.

There is certainly room for humans to evolve technologically as well as sociologically. There is much that we do not know in Physics, and Engineering can always get better. It would seem likely that we will develop machines that are more intelligent than anything we have now. Given abundant resources, it would seem logical to send them to explore the rest of the solar system and eventually other solar systems.

Machines would also maintain continuity of purpose and memory required to complete projects that could take thousands or even millions of years. Humans would presumably eventually develop the technology to integrate their memories and consciousness with those of the machines, leaving biological bodies behind.