Appearances are a glimpse of the obscure.

What one man can invent another can discover.

How gloriously legible are the constellations of the heavens!

Every man takes the limits of his own field of vision for the limits of the world.

One sees great things from the valley; only small things from the peak.

Nature has planted in our minds an insatiable desire to seek the truth.

The eternal mystery of the world is its comprehensibility.

The unknown is the largest need of the intellect.

Science is a cemetery of dead ideas.

I learned to make my mind large, as the universe is large, so that there is room for paradoxes.

I am tormented with an everlasting itch for things remote. I love to sail forbidden seas and land on barbarous coasts.

What one man can invent another can discover.

The atavistic urge toward danger persists and its satisfaction is called adventure.