There is a famous anecdote, attributed apparently to Niels Bohr:
A journalist visited home of a Nobel prize winning scientist. The visitor was surprised to find a horseshoe above the front doorway of the scientist’s abode. Tradition asserts that a horseshoe acts as a talisman of luck when placed over a door.
The visitor asked the physicist about the purpose of the horseshoe while expressing incredulity that a man of science could possibly be swayed by a simple-minded folk belief. The physicist replied:
- Of course I don’t believe in it, but I understand it brings you luck, whether you believe in it or not.
Scientist are humans. Humans have faith in both silly things like horseshoes and "lucky socks" and not so silly things like religion or love.
In the movie itself:
She’s in love with Wolf Edmunds
Yes. And that makes me want to
follow my heart. But maybe we’ve
spent too long trying to figure all
this with theory -
You’re a scientist, Brand -
I am. So listen to me when I tell
you that love isn’t something we
invented - it’s observable,
powerful. Why shouldn’t it mean
It means social utility - child
rearing, social bonding -
We love people who’ve died ...
where’s the social utility in that?
Maybe it means more - something we
can’t understand, yet. Maybe it’s
some evidence, some artifact of
higher dimensions that we can’t
consciously perceive. I’m drawn
across the universe to someone I
haven’t seen for a decade, who I
know is probably dead. Love is the
one thing we’re capable of
perceiving that transcends
dimensions of time and space. Maybe
we should trust that, even if we
can’t yet understand it.
So Brand is willing to follow her feelings, saying that "love might have higher meaning". It is not a plot hole - it is being human.
There is a fragment from the "I, Robot" movie where scientist explains, why robot rescued adult instead of a child from a car accident - "The adult had a higher chances of survival". "Yes, - says the police officer - but humans know, that you always go for child first. It is what humans do."
Scientists are not any different.