There's not much suggesting that there is only one Great Filter. After all, we haven't met anyone else yet, so the likelihood of another filter being in our fut

There's not much suggesting that there is only one Great Filter. After all, we haven't met anyone else yet, so the likelihood of another filter being in our future is just as real as it is if there was one in our past. Call it the "two neptune filter", to borrow from the article. :-)