THE COMPUTATIONAL METHOD at the heart of Pascal's work was actually discovered by a Chinese mathematician named Jia Xian around 1050, published by another Chinese mathematician, Zhu Shijie, in 1303, discussed in a work by Cardano in 1570, and plugged into the greater whole of probability theory by Pascal, who ended up getting most of the credit. But the prior work didn't bother Pascal. "Let no one say I have said nothing new," Pascal argued in his autobiography. "The arrangement of the subject is new. When we play tennis, we both play with the same ball, but one of us places it better."
That is from The Drunkard's Walk: How Randomness Rules Our Lives by Leonard Mlodinow, an excellent book and an easy read. This passage should remind of us two things:
1) Sometimes astonishing insights can lie around for hundreds of years (in this case six centuries!) before they are widely recognized and applied.
2) Real innovation often comes about through the novel combination of existing ideas or approaches. We tend to dismiss the power of existing ideas as "old hat" or "already known." Instead, we believe that addressing our challenges or problems requires entirely new insights (preferably by lonely geniuses). That is a big mistake: combining, tweaking, and applying existing ideas or approaches is what causes most real breakthroughs.