But I would say:
1. reproduce, have kids 2. keep what your ancestors gave you and make it better
Be a doer and a thinker. The Admiral was also right.
1) According to most cosmological models the universe will eventually end.
2) Even if it didn't, the problem with infinity is that anything that can possibly happen will happen, including the extinction of everything ever descended from ourselves.
One is forced to consider that the journey must be more meaningful than the destination.
Not necessarily. There are different cardinalities (sizes) of infinity. Your statement can only be true if the cardinality of time is at least as high as the cardinality of all possible events; I don’t know enough math (or physics) to pin either of these down, but it’s not obviously true.
People reproduce for the same reasons any other species reproduces though; they are a vehicle for their genetic code. That's what biological life is and we are not somehow separate or unique from the rest of nature in that regard.
To do that just because it is my biological imperative has never seemed like a very good justification to me. So my ancestors all reproduced over the cause of many millennia and that means I should also reproduce...why exactly? To continue the bloodline? For what purpose? I don't have any interest in being a part of that.
Your second point seems sensible though. Don't make things worse while you're here, leave it the same or better and try to live your life without causing harm to others.
I tend to believe that life is mostly suffering (and for most of the world it demonstrably is) sporadically dotted with short periods of joy or contentment. None of us have a choice in being born but the least we can do is try to make life easier for ourselves and everybody else as we struggle through this experience in quiet desperation.
Beyond that it all starts to sound like baseless ideology and narrow-minded religion pushed on us by people who desire to (with futility) control all the variables in their own subjective experience of this life.
(aside: it's funny how always similar things come up in batches https://twitter.com/elonmusk/status/1141977875567919104)
B) you're free to live on the Moon or on Mars once(IF) it becomes possible but 1) the ticket price is VERY expensive 2) once the novelty has faded, there's a very real possibility that you're going to be very jealous of those who can breath 'fresh air' outside. 3) these colonies are only useful for humanity if there are self-sufficient but they need high technology to just continue to exist, so how can they become self-sufficient? How are you going to make solar panels on Mars with only what is available on Mars?
2) I don't think i would be jealous of those who can breath 'fresh air' , i already spend most of my time in a room, and with better VR games and large domes/caverns i don't think i'll miss the outside.
3) Again with large population on earth, there will be enough people who want to go to mars to create self sufficient economy there.
A) the amount of generated waste does not depend only on the population but also on the time the population lives at the given level of technology. When there are less people less resources are spent on science, and people end up generating the same amount of waste eventually, and do not develop the knowledge required to generate less waste. Another variable is the desire to generate less waste: as long as the amount of the waste is not threatening most of the people are not interested in generating less of it. Some see the problem sooner than others, but with lower population the number of these people is also lower and they have smaller effect.
If you look at the history of humankind you'll see that we were able to do great harm to environment even with much smaller numbers (killing megafauna, deforestation). the difference was that then we were not able to understand what was happening.
The crucial point is that the cost of developing new technologies does not depend, but reward grows, with the number of people alive. So when the number of people grows, everyone wins.
I believe the myth of overpopulation and the cultural norm to have less children, have caused great harm. Migration from poorer high birthrate countries into rich low birthrate countries leeches the most important resource the poor countries have, more educated and more active people who want to change the country. If developed countries were giving as many migrants as they take, we would be living in a much better world. Hopefully technologies like longevity therapies and artificial womb will be developed sooner than the population starts to decline.
Well, "progress" in itself isn't either, as it lacks direction (progress towards what? Why would new be better?).
At least tradition has the "tried" part working for it, and it's something you know the pros and cons and how to work with it (even if its a devil, it's "the devil you know"). It's also a good choice if one values stability over volatility...
So we shouldn't blindly follow it, but should throw it just because there's something new.
A better question (we seldom ask) is: do we want this something new. Many times the new is just imposed into us (e.g. just because it's possible or profitable).
It's only that a lot of what is disguised as "good old tried stuff we call tradition" is highly subjective stuff that's barely one or two centuries old, which means, it's not old, it's not really tried either, so it likely is not "good" per se, but highly contextual.