All the talk about looking for earth-like planets to find extraterrestrial life could be a big waste of time if we eventually learn that present-day conditions on Earth are not conducive to creating the fundamental building blocks for life

The only way we can do this is by exploring other worlds. We can only infer what happened in our past, but if we see life elsewhere we can assume some general set of conditions that caused it. If we look and don't find it, then we must assume life on earth is a fluke.