Your Faith and Extraterrestrial Life

[Polymath257]

Since we have absolutely no idea how often life forms in the universe or the likelihood of life forming, how could we have any idea whether other life exists or not?

The main piece of data is how quickly life formed on Earth and how many Earth-like planets are expected.

Bacteria appeared on Earth very quickly after conditions for such life became reasonable possible (liquid water, for example). But, getting beyond that took billions of years on Earth, which suggests that multicellularity is very difficult to achieve. After that, it took another half a billion years to get to humans. And it isn't clear that humans will last 20,000 years of having agriculture.

What do I conclude? Bacterial life is easy. Multicellular life is very difficult. Intelligent life isn't easy, but happens fairly quickly once multicellular life happens. Hence, I expect bacterial life to be common, but multicellular life to be rather rare. Intelligent life, I expect to happen, but probably to not last long.

And, you are right, this is a wild guess based on one example. I could be completely wrong one way or the other.

 

[Almighty God]

The main piece of data is how quickly life formed on Earth and how many Earth-like planets are expected.

Bacteria appeared on Earth very quickly after conditions for such life became reasonable possible (liquid water, for example). But, getting beyond that took billions of years on Earth, which suggests that multicellularity is very difficult to achieve. After that, it took another half a billion years to get to humans. And it isn't clear that humans will last 20,000 years of having agriculture.

What do I conclude? Bacterial life is easy. Multicellular life is very difficult. Intelligent life isn't easy, but happens fairly quickly once multicellular life happens. Hence, I expect bacterial life to be common, but multicellular life to be rather rare. Intelligent life, I expect to happen, but probably to not last long.

And, you are right, this is a wild guess based on one example. I could be completely wrong one way or the other.

That's a reasonable analysis, although as you already stated we don't know that the speed at which bacterial life formed on earth would be matched on other planets with similar environments. I tend to agree that extraterrestrial life exists, mostly because of the weirdness of earth being the only planet with life in a universe of billions of planets. But I'm not very confident about it because I have no evidence for it.

 

[ppp]

What do I conclude? Bacterial life is easy. Multicellular life is very difficult. Intelligent life isn't easy, but happens fairly quickly once multicellular life happens. Hence, I expect bacterial life to be common, but multicellular life to be rather rare. Intelligent life, I expect to happen, but probably to not last long.

Not a disagreement, per se. But it could be that multicellular life is not evolutionarily advantageous until enough of the unicellular niches are filled. In complexity and/or quantity.