every time we exercise self-criticism, every time we test our ideas against the outside world, we are doing science. When we are self-indulgent and u… - Carl Sagan

We hear the crack of a bullwhip because its tip is moving faster than the speed of sound, creating a shock wave, a small sonic boom. A thunderclap has a similar origin. It was once thought that airplanes could not travel faster than sound. Today supersonic flight is commonplace. But the light barrier is different from the sound barrier. It is not merely an engineering problem like the one the supersonic airplane solves. It is a fundamental law of Nature, as basic as gravity. And there are no phenomena in our experience — like the crack of the bullwhip or the clap of thunder for sound — to suggest the possibility of traveling in a vacuum faster than light. On the contrary, there is an extremely wide range of experience — with nuclear accelerators and atomic clocks, for example — in precise quantitative agreement with special relativity.

Un asombroso declive de la expectativa de vida, el aumento de la mortalidad infantil, las violentas epidemias de enfermedades, las condiciones sanitarias por debajo del mínimo y la ignorancia de la medicina preventiva se unen para elevar el umbral a partir del cual se dispara el escepticismo de una población cada vez más desesperada

You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep seated need to believe.