That's right. But it does create doubt. To prove, we would need to find such life. To not have doubt, we need to have a reasonably high confidence that such

That's right. But it does create doubt. To prove, we would need to find such life. To not have doubt, we need to have a reasonably high confidence that such life is there. However, the estimates are so wild and range from very unlikely to no-doubt. Thus, there is doubt (to the best we understand).