“Science knows no country, because knowledge belongs to humanity, and is the torch which illuminates the world.” – Louis Pasteur (via ScienceAlert on Facebook, where you can find many cool things.)
At ScienceAlert I also found this wonderful quote from Neil deGrasse Tyson: The good thing about science is that it’s true whether or not you believe in it.” (This is particularly relevant to a discussion we’ve been having over at SciBlogsNZ about interactions between scientific attidudes and people’s belief systems.)
Readers – please feel free to add your own favourite quotes to the list :-)

It’s not exactly a quote but the title of Carl Sagan’s book “The Demon-Haunted World: Science as a Candle in the Dark” is pretty damn good.