A scientist naturally and inevitably ... mulls over the data and guesses at a solution. He proceeds to testing of the guess by new data-predicting the consequences of the guess and then dispassionately inquiring whether or not the predictions are verified.

Equipped with our five senses - along with telescopes and microscopes and mass spectrometers and seismographs and magnetometers and particle accelerators and detectors sensitive to the entire electromagnetic spectrum - we explore the universe around us and call the adventure science.

Wisdom cannot be directly transmitted, and does not readily accumulate through the ages.

There we measure shadows, and we search among ghostly errors of measurement for landmarks that are scarcely more substantial.

All nature is a vast symbolism: Every material fact has sheathed within it a spiritual truth.

At the last dim horizon, we search among ghostly errors of observations for landmarks that are scarcely more substantial. The search will continue. The urge is older than history. It is not satisfied and it will not be oppressed.

The great spirals, with their enormous radial velocities and insensible proper motions, apparently lie outside our Solar system.