It stands to reason that any civilization is gonna see its share of challenges. I mean, look at the dinos. They had this shit on lockdown for near 165 million years and, well, let's just say when you prioritize eating each other over a well-funded science program, you're not gonna deflect that asteroid.
We went from single-cell to multi-cell, grew fins and learned to walk, we've seen wars and pestilence, plagues and droughts, floods and freezes over our paltry 200,000 years. But we made it! Until now. What I'm trying to say is, we have put ourselves in a goddamn precarious position, all in the name of progress. We don't make wars by donning tri-corner hats and marching in straight lines and stabbing each other anymore. We make it go boom from far, far away. We've bottled up those aforementioned plagues and diseases and keep them in a Kitchen-Aid for some god-forsaken reason. Half of us are eating ourselves to death. What I'm really trying to say is, just because we've made it to this point, doesn't mean we're gonna continue.
And that's the Great Filter. The theory being, at some point, every civilization faces a true breaking point: nukes, disease, asteroid, environment, star goes supernova. Whatever. The point is either they make it, or they don't.
You're probably wondering: how this relate to us, and the search for E.T.?
Scenario #1: "I thought you said we're fine", OR: The Great Filter is behind us (OR: more technically, the "Rare Earth Hypothesis")
One prevailing theory is the graduation to multi-celled life was our Great Filter. The right time in organic history, Earth's history and the solar system's history. The planets just "lined up" (KILL ME). Incredibly rare. The odds were decidedly not in our favor for that one, and now look: Tinder!
This cheats a little because it veers away from the thought that Great Filters tend to occur when a civilization is on the brink of incomprehensible technological greatness. That is, everything we've discovered and built turns against us. That just before we can travel the stars, we kill ourselves. But anyways. In Scenario #1, we made it! We're on the way to becoming a Type III civilization, capable of colonizing whatever the fuck we please.
Why this sucks: If it's so rare, and we're the only ones that made it, we're probably alone.
Why this rocks: We're #1! We're gonna make it!*
Scenario #2: The Great Filter is in front of us, OR: Better get that fucking rocketship program back underway
Let's look at all the shit that could kill us in the near future. Just the near future. Comprehensive, nature and human induced climate change, leading to complete environmental destruction. A hard reset. Nuclear war. Asteroids. Synthetic pandemics. Skynet.