A little science estranges men from God, but much science leads them back to Him.
Attr. Louis Pasteur
Pasteur was a Catholic, and he did believe that science leads a man towards belief, but did he say this? Wikiquote says no, saying that it was attributed to him in God Doesn’t Believe in Atheists (2002) by Ray Comfort. I can verify via Google Books that the alleged quotation is there, but the book uses endnotes, not included in the preview, so I can’t tell if he gives a citation.
Searching Google Books turns up a lot of attributions to Francis Bacon, which Wikiquote also provides. But it also turns up some attributions to Pasteur dating from well before 2002. I thought I’d found one that went all the way back to 1920. When I looked at it, I found that it was a reprint of a letter discussing whether or not Pasteur was a practicing Catholic. The last line of the letter says, “I believe that this will satisfy anyone. that Pasteur was a faithful child of the Church, and his example is another example of the words of Pascal that ‘a little knowledge estranges one from God, whilst great knowledge brings one closer to God.’ ”
Pascal?
At this point, I gave up. (I did search for other attributions to Pascal, without success.) I tend to think that Pasteur did not say it, but I am far from sure.
I have edited Wikiquote appropriately.
They didn't say it 