Jonas Salk on Polio
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“It is courage based on confidence, not daring, and it is confidence based on experience.”
“There are three stages of truth. First is that it can't be true, and that's what they said. You couldn't immunize against polio with a killed-virus vaccine. Second phase: they say, "Well, if it's true, it's not very important. And the third stage is, 'Well, we've known it all along."”