Absence of proof is not proof of absence. — Michael Crichton. American author and filmmaker (1942–2008)
Each generation writes off earlier errors as the result of bad thinking, of less able minds--and then confidently embarks on making fresh errors of its own.
Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you're being had.
The belief that there are other life forms in the universe is a matter of faith. There is not a single shred of evidence for any other life forms, and in forty years of searching, none has been discovered. There is absolutely no evidentiary reason to maintain this belief.
Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled.