Pliny the Elder (20-79)

Gaius Plinius Secundus, known in English as Pliny the Elder, was a Roman author, naturalist, scientist, naval and army commander of the early Roman Empire, procurator, and friend of the emperor Vespasian. Pliny wrote the encyclopedic Naturalis Historia, a thirty-seven-volume work covering a vast array of topics on human knowledge and the natural world, which became an editorial model for encyclopedias. He spent most of his spare time studying, writing, and investigating natural and geographic phenomena in the field.

Quotes

In these matters the only certainty is that nothing is certain.

Uncertainty
Why is it that we entertain the belief that for every purpose odd numbers are the most effectual?
To conclude, all other living creatures live orderly and well, after their own kind: we see them flock and gather together, and ready to make head and stand against all others of a contrary kind: the lions as fell and savage as they be, fight not with one another: serpents sting not serpents, nor bite one another with their venomous teeth: nay the very monsters and huge fishes of the sea, war not amongst themselves in their own kind: but believe me, man at man's hand receiveth most harm and mischief.
In comparing various authors with one another, I have discovered that some of the gravest and latest writers have transcribed, word for word, from former works, without making acknowledgment.

Writing
Indeed, what is there that does not appear marvelous when it comes to our knowledge for the first time? How many things, too, are looked upon as quite impossible until they have been actually effected?
There is always something new out of Africa.
The best plan is to profit by the folly of others.
This only is certain, that there is nothing certain; and nothing more miserable and yet more arrogant than man.
From the end spring new beginnings.
No mortal man, moreover is wise at all moments.
True glory consists in doing what deserves to be written; in writing what deserves to be read; and in so living as to make the world happier for our living in it.
The only certainty is that nothing is certain.