Fragments

What survives of Democritus

Nothing Democritus wrote survives complete. These 5 lines reached us only because later writers copied them into works of their own, usually while arguing about something else.

DK 68 B9, Wording secure
Sextus Empiricus, Against the Logicians I.135 (c. 200 CE)
A sceptic collecting earlier arguments that the senses do not report the world as it is. He kept the sentence because it was the strongest version of the claim he could find.
The founding statement of atomism survives inside an argument for doubting the senses, made by someone who was not an atomist.
DK 68 B125, Wording likely his
Galen, On Medical Experience 15.7 (c. 180 CE)
A physician arguing that medicine cannot do without the evidence of the senses. He quoted the senses answering back, because a doctor who distrusts what he observes has nothing left to work with.
Democritus lets the senses reply to the mind that had just dismissed them. It is preserved in Arabic and Latin translation as well as Greek, which is how we know Galen was not inventing it.
DK 68 B117, Wording likely his
Diogenes Laertius, Lives of the Eminent Philosophers IX.72 (c. 230 CE)
A compiler of philosophers' lives listing the ones who had doubted knowledge, to show the sceptics had a long pedigree. The line is filed as a credential rather than explained.
DK 68 B191, Wording likely his
Stobaeus, Anthology III.1.210 (c. 450 CE)
An anthologist filing extracts under moral headings. This one went under self-control, alongside sayings by people Democritus would not have recognised.
The atomist survives mostly as a moralist, because that is the shelf the anthologies had room for.
DK 68 B247, Wording likely his
Stobaeus, Anthology III.40.7 (c. 450 CE)
Collected under exile, among consolations for people who had been driven from home.