The author uses the example of the question of life in other galaxies primarily in order t

A．question whether in certain situations the truth may ever be determined

B．illustrate that truth has an objective existence even when there are few empirical grounds for determining it

C．suggest that the answer to certain scientific questions plays only a minor role in people's lives

D．support the thesis that skepticism plays a vital role in the scientific process

E．assess the answers pseudo-sciences like ufology provide for unanswerable questions