I'd like to state up front that I am a fan of Neil Degrasse Tyson - I fully approve of his mission to raise the profile of science, particularly since America seems to have a really low opinion of the subject to begin with (can you name an American scientist? The British can name dozens, or more, of their own). If I haven't gotten to watch Cosmos yet, it's only because I have limited time to hang out watching on-demand TV at my mom's house. But I want to get to it.
My main exposure to him, therefore, is through the Nerdist Podcast (maybe they should start advertising here?). He's been on the show three times now, and his discussions have always been fascinating, not to say mind-bending - the first time he described the 4-dimensional hypercube, or a cube in four (spatial) dimensions.
But - and this is in full recognition of the fact that Dr Tyson is enormously smarter than I am - sometimes he says some silly, silly things. Or at least, things I disagree with (I sometimes have trouble telling the difference). Case in point: in his third appearance on the Nerdist, Dr Tyson takes issue with the statement that "life always finds a way", pointing out that 97% of all species that have existed on Earth have gone extinct.
My response is, this latter fact doesn't prove that life doesn't find a way - it just proves that the species who make up that unfortunate 97% didn't. On the other hand, the fact that we're here to debate the point seems to indicate to me just how tenacious life is.
Put another way, there have been times when the planet's climate has been seriously inimical to life, for instance in the exact moment that the asteroid that wiped out the dinosaurs hit the Earth. As scientists in movies like to say, that was an extinction-level event. But while it wiped out a great many species, it didn't wipe them all out, because I'm here typing these words, and, one hopes, you're reading them. We couldn't be doing this if our shared rat-like ancestor (and more to the point, its entire species) had perished along with the dinosaurs.
Of course, I don't want to put too much faith in a throwaway line from "Jurassic Park", but you also don't need to look that far back to find examples that disprove Dr Tyson's critique of the "life finds a way" statement. As you head to certain areas, you find amazing adaptations to extreme conditions - camels that can cross deserts by hoarding water in their humps, Australian trees that have adapted to survive in landscapes full of elements that would kill other trees... even the creatures that live at pressures that would crush us in an instant.
And then there are the extremophiles. These are creatures - mainly in the form of bacteria, or other one-celled organisms - that can survive extremes of heat, cold, radiation, salinity. Essentially any condition that the vast majority of organisms on Earth would not be able to survive in. And this isn't theoretical - according to David Toomey's book, Weird Life, bacteria have been found in nuclear reactors and living in hard vacuum, on board satellites.
The point is that, while another asteroid strike right now would wipe out a great many species (most notably our own), it certainly wouldn't kill everything on Earth. The only creatures to survive would probably be rats and cockroaches, but within a few million years they could repopulate the planet and fill all of the vacant niches. The only thing that could conceivable destroy all life on Earth, from the macro to the micro level, is the Sun expanding to engulf the planet. And one hopes that by the time that happens, we'll have figured out a way to get out into the rest of the universe (or our rat-people successors, if not their sworn enemies, the cockroach-folk).
On the other hand, Mars may stand as a rebuke to my argument. There's evidence to suggest life may have existed there, but no smoking gun. If we discover that life did exist there, then we'll have to ask two questions: is it still there now, and if not, why? If life did once exist on Mars, but doesn't now, then I can accept Dr Tyson's argument - ignoring the observer effect bias that comes from the fact that life forms from one planet are going next door to discover that an entire ecosystem has failed.
My point here - and again, I stress this with the utmost respect for his achievements - is that just because someone's smarter than us, not everything he or she says is correct. I was intrigued that nobody in that podcast's comments section called Dr Tyson on that specific statement. They argued about science's relationship to philosophy, but because he said a whole lot of other spot-on things, then threw a number followed by the word "percent" at us, they didn't dig any further.
And while Dr Tyson may not agree with all that I've written above, he would surely agree when I say that if we want to become a more scientifically literate society, we need to stop being intimidated by numbers and statistics, and the people who use them to make points. Because Dr Tyson's comments are intended for entertainment and edification - others aren't afraid to present statistics to advance less-noble causes.