Extinction dooms all life because there’s no shot at advanced tech or space colonization without humans

First, the big picture. We've got hundreds of millions of years left on Earth if nothing very bad happens first. If we can keep our civilization going, we've got much, much more time ahead of us in space colonization. But humanity may be Earth-originating life's only shot at colonization. Given the apparent lack of other intelligent life out there (the Fermi paradox), the fate of life in the universe may well be in our hands. I'd say everything else we could concern ourselves with simply pales in comparison to the fate of life in the universe! Given the many non-trivial threats to our survival we currently face, I recommend focusing on protecting our survival until we drive the risk of our extinction down to right around zero.

Political Ideologies

Political ideology is not my expertise, so the writing may be a bit off the mark. In the comments, correct me if you can. I include this section because I hope that human survival can be something we unite behind and not a partisan issue.

For progressives

Assuming that "progress" here is largely a human phenomenon, and thus, without humans, no more progress. All other progressives' efforts, such as reducing poverty or corruption or improving education or the environment are for nothing if something else comes along and takes us out. (The idea that human extinction might be good for the environment is addressed below.) Meanwhile, progressives already lead extinction-prevention measures such as climate change mitigation (see HE 3: Critical Review of DK Diaries or the Al Gore quote below for more).

For conservatives

If we are to "conserve" how things have been, then conserving our existence is an important first step, similar to "progress" above. Also, where conservatives are concerned with national security, seeing as our nation is part of humanity, if humanity's gone, then so is the nation. So calling an extinction risk a national security threat is if anything an understatement.

I apologize here for perhaps supporting the frame that progressives are better on the environment and conservatives are better on national security. Both can be quite good on either, i.e. by "conserving" the environment or making "progress" on national security.

For libertarians

As the saying goes, "Your rights end where my nose begins". Well, if humanity goes extinct, then that's a lot of noses gone. For more, see the discussions of rights and potential people below.

For the religious

See discussion of eschatology below.

Philosophical Ethics

Here, in a "Socratic method-meets-isolated blogger" fashion, I'll ask myself a series of questions and then answer them. This is perhaps more thorough than it needs to be, but it can't hurt for us to brush up a bit on our philosophy, right? :)

Does the term "Most Important Thing To Work On" have any meaning in the first place?

Ahh! Meta-ethics! Is there such a thing as right and wrong? Does objective morality exist? This is ye ole is-ought problem: Can we discover or deduce what we ought do from how the world/universe is? The scientist in me says, quite emphatically, No. If we want any sort of morality, we're just going to have to make some stuff up. I'm OK with that. However, it does mean on some deep level, I technically can't disagree with anyone on moral matters (again, hence "One View"). Whatever your views, hopefully you still reach the same conclusion on the priority of preventing human extinction.

Related: Can science take stands on issues?

Should we make any sacrifices for anyone else?

The view that says no, we shouldn't is called ethical egoism. Unless we reject it, we can't recommend anyone do anything they don't want to help anyone else, whether it's donating to charity or saving the world (or donating to a charity that saves the world...). While I expect (and hope) everyone here rejects this view, it does play a role in the hyper-individualistic, free market, anti-sacrifice side of our culture. See for example Rep. John Shadegg (R-AZ) on climate change:

We must be careful not to enact policies that will unnecessarily impose a financial burden on American families.

Take out the word "unnecessarily" and you basically have ethical egoism. I'm not sure what constitutes necessity here, but if anything does, protecting our survival does.

For ethical egoists, perhaps the only thing we can do is work on life extension- if they're not going to die from aging, then they'll become more concerned about dying from some extinction event. But for the rest of us, some sacrifice is not unreasonable. Al Gore said it well (discussing climate change in Rolling Stone):

There's a philosophical question embedded in what you're asking: Is this important enough for us to make sacrifices? The answer is yes, of course - we're talking about the survival of human civilization.

Related: Pareto Optimality (on Felicifia), a similar concept that's popular in mainstream economics- unfortunately, because it also fails to ever call for any sacrifices. As Nobel Laureate and champion of the poor Amartya Sen says, "a society can be Pareto optimal and still be perfectly disgusting".

Can we go extinct?

I include this as a philosophic question (in addition to a scientific one) as a nod to eschatology, i.e. the study of the end of the world. If our religious or other beliefs include the idea that something will pull a deus ex machina and save us from extinction at the last minute, then we don't need to try protecting our existence ourselves. While I do generally get along with religion well, where it would threaten our very existence, I must object. From asking around a bit, I know of no religious groups that would actively try to cause human extinction. My sense is that most would also support trying to prevent human extinction, but my knowledge here is less thorough. (What would John Hagee do?) Anyone here know better?

Related: Has The Rapture Already Begun? by Vyan.

Should we go extinct?

I include this as a nod to the Voluntary Human Extinction Movement. In their words, "the hopeful alternative to the extinction of millions of species of plants and animals is the voluntary extinction of one species: Homo sapiens... us." (link) That humanity is causing many species extinctions is quite true- see the Holocene/Anthropocene extinction event. If our goal is to maximize the number of species that survive this event, then VHEMT is maybe onto something. However, over the long term, if Earth-originating life is going to survive, we're probably going to be the ones to make it happen. Earth almost definitely won't be hospitable forever unless some advanced technology makes it happen, and if it doesn't, some space colonization will be necessary. So, humanity's extinction would probably actually doom the rest of life on Earth. Thus, when we talk of preventing humanity's extinction, we're effectively talking about ensuring the continued existence of Earth-originating life, which, for all we know, is the only life in existence.