The world we have created is a product of our thinking.

Here's a Challenge: Study a complicated topic in such detail that anyone interested can nod their head and understand as you explain specific concepts within the topic.

Despite my being an old gypsy there is a tendency to respectability inherent in old age.

Pure mathematics is, in its way, the poetry of logical ideas. ... [By seeking] logical beauty spiritual formulas are discovered necessary for the deeper penetration into the laws of nature.

I see in Nature a magnificent structure... that must fill a thinking person with a feeling of humility.

One should not pursue goals that are easily achieved. One must develop an instinct for what one can just barely achieve through one’s greatest efforts.

I think we have to safeguard ourselves against people who are a menace to others, quite apart from what may have motivated their deeds.