An optimist may see a light where there is none, but why must the pessimist always run to blow it out?

In the long run the pessimist may be proven right, but the optimist has a better time on the trip

I'm not a pessimist at all, but I'm not an optimist, either.

His (my father's) general belief in life's well-being worked either way. 'Have you ever had it before? You have? It's not going to kill you, then. If you've had the same thing before, you'll be alright in the morning.' My mother couldn't have more profoundly disagreed with that. 'You're such an optimist, dear,' she often said with a sigh. 'You're a good deal of a pessimist, sweetheart.' 'I certainly am.' And yet, I was well aware as I stood between them, he the optimist was the one who was prepared for the worst, and she the pessimist was the daredevil.

I am by nature an optimist and by intellectual conviction a pessimist.

The two operations of our understanding, intuition and deduction, on which alone we have said we must rely in the acquisition of knowledge.