From Burnet's Note on the Sources
The scrap-book which goes by the name of Diogenes Laertios, or Laertios Diogenes (cf.Usener,
Epicurea, pp. 1 sqq.), contains large fragments of two distinct doxographies. One is of the merely
biographical, anecdotic, and apophthegmatic kind used by Hippolytos in his first four chapters; the
other is of a better class, more like the source of Hippolytos' remaining chapters. An attempt is made to
disguise this "contamination" by referring to the first doxography as a "summary" (κεφαλαιώδης) account,
while the second is called "particular" (ἐπὶ μέρους).