Well, personally, I'm studying to be a biology teacher, so I'm partial toward Mendel as the field that I'm studying would be so different without him. But, on the whole, Galileo probably wins from a more ob
Of the two choices, I would opt for Galileo. (If I were allowed to have a write-in candidate, I would choose Newton.)
Although he didn't invent the telescope (as I was wrongly told in grammar school), he did point it towards the planets and stars. His observation of Jupiter and its four largest planets, gave proof that not all things revolve around the earth in crystalline spheres.
This was in direct opposition to the writings of the church, and he was called a "revolutionary" (BECAUSE of Jupiter's moons "revolving" around the giant planet), and was one of the first people to begin experimentation in order to answer questions, rather than people just philosophizing about how things worked.
I would find Galileo more interesting because of the way he pissed off the established church of the time.
Galileo. No contest.
Galileo for having the b*lls to tell the church what he believed - even though he knew it could kill him, whilst Mendel didn't even mange to get his ideas out there until after his death.
Galileo. I am simply FASCINATED to read of his life and discoveries, and his harsh punishments. If I could talk to a dead person, it would be him.
Galileo. Mendel made pea soup.