Subtitle: We don't have a reason, we just wanna.
I was listening to entirely secular but very agreeable people discuss Elon Musk, Jeff Bezos, NASA and the advantages of manned versus unmanned space exploration and had the overwhelming feeling that nothing has changed since I first started thinking seriously about this after reading CS Lewis's Out of the Silent Planet in the 1980s. There are important philosophical issues that should be undergirding any such discussion which are simply absent. It is not as if I am finding they are disagreeing with my premises so much as they are simply oblivious to any of it.
They discuss one possible motivation for much-more expensive manned travel and eventual settlement that humankind might somehow "need" this, because of environmental or geopolitical problems. We might need to have a place to settle ourselves because we have rendered this world...what? Too dirty even though 8B of us are surviving here so that we have to find a way to get a few hundred of us off the earth to "rescue" the species? Whew. We got a few of us onto Mars or Europa just in time, eh? Mankind is saved! Or because the first moon landing was all about America showing its primacy, maybe a Mars trip could be a joint affair with America, Russia, Europe, China and India! This would be about cooperation instead of competition and geopolitical warfare this time. And that would clearly be so much better for the 8B of us because...why, exactly?
One of the participants actually did say "It's an interesting question whether we think spreading across the galaxy really is mankind's destiny." What is this destiny you speak of? Mankind has a destiny? Who says? Who gave us this destiny? If you think this isn't our destiny, on what basis do you think we have any destiny at all? These are frankly, the smartest and most tech-savvy and connected people in the world, and these questions don't even seem to occur to them. The discussion quickly reverts to the technical difficulties. But even more worrisome, they seem to have some dim awareness that people might not consider this valuable, and always, always move immediately to "It's like the settling of the New World, or of Australia. There were risks and not everyone made it, but it generally worked out." The question switches again from "is this morally justified" to "Will this eventually pay itself back?" or "But isn't this just a great adventure?" With the question of "why?" being quickly shuttled off to "You must just be objecting to the risk or the cost, and we just covered that."
The questions do not even occur to them. For decades many of us have stroked our chins and said "All these teleological assumptions and moral justifications will have to be addressed sometime," but the reality is No they won't. It's not that these people aren't going to come to answers to these questions we find suspect. It's that they aren't going to answer them at all. They are going to Mars because they wanna. Any challenge gets diverted into irrelevant questions.
One interesting bit of this is to reflect this back to the exploration of the New World. Those people and the settlers who came after are accused of many bad motives, such as seeking money or slaves. There is some truth in that, probably. There are also the justifications of Europeans trying to spread Christianity or Civilisation, which is now regarded as an especial colonialism and evil. But I think we are overlooking what we see in front of us now in a similar situation. Some wanted adventure or to get rich, but most of the sailors and settlers just wanted a job. Shucking clams might have taken them instead if circumstances had been slightly different. Glory? Maybe a few. But mostly, people had no real reason at all. They just wanted to. Just like now.
Folks like us read CS Lewis and still debate what mankind's proper action should be,of the few hundred out of 8B of us. I don't think it matters. We can say until we are blue in the face that it is necessary to answer these values questions. I guess not. All of these discussions are just spilling over with unquestioned values and...so? Does it change anything? They are going to do it anyway,and there will be some vague default answer for the underlying justification. But mainly it's going to be "But we wanna."