Optimism has long been a subject of Western traditions of philosophy. It has often been studied alongside concepts like realism which it is sometimes contrasted against. Gottfried Leibniz wrote about positive thinking and optimism, famously saying that the best of all possible worlds is the one that actually exists, to paraphrase his writings somewhat. Blaise Pascal was another philosopher who built on Leibniz's thoughts, saying that people should embrace the whole universe rather than being overwhelmed by it.