photo neededIn existographies, Diogenes Laertius (c.190-250AD) (IQ:155|#505) (CR:31) was Greco-Roman historian noted for his circa 230 The Lives and Opinions of Eminent Philosophers, oft-cited for a number of historical topics, such as discussion of Democritus, monad theory, Zeno of Citium and the slave stealing parable (Ѻ), the existographic data on Epicurus, being and nonbeing, etc.

Democritus | Atomic theory
Laertius summarizes Greek philosopher physicist Democritusatomic theory model as follows: [1]

“The principles of all things are atoms and the void, and everything else exists only by convention. The worlds are unlimited and subject to generation and corruption. Nothing could come to be from nonbeing, and nothing could return by corruption to nonbeing. Atoms are unlimited in size and number, and are the seat of a vortex motion in the universe, which results in the creation of all compounds: fire, water, air, and earth, which are simply organizations of certain atoms, themselves resistant to change and alteration by virtue of their hardness. The sun and the moon are composed of such particles, smooth and round, as is the soul, which is the same thing as the intellect.”

Laertius, in his The Lives, published list of Democritus’ works, were many and encyclopedic in scope, including: astronomy, mathematics, literature, epistemology, and ethics—none of which, however, survived. [3]

Monad
Laertius, citing Hippolytus, states that the term “monad” originated in the works of Pythagoras and or his followers (Pythagoreans), who called the first thing that came into existence the ‘monad’, which begat the dyad, which begat the numbers, which begat the point, begetting lines or finiteness, etc. [2]

See also
Diogenes of Apollonia (c.460-400BC) (FA:14) Greek air principle philosopher
Diogenes (c.408-323BC) (Cattell 1000:N/A) [RGM:386|1,310+] (PGT:2|Li) (Ѻ) Greek cynic philosopher
Diogenes of Oenoanda (c.77-142AD) Greek Epicurean philosopher

References
1. (a) Pullman, Bernard. (1983). The Atom in the History of Human Thought: a Panoramic Intellectual History of a Quest That Has Engaged Scientists and Philosophers for 2,500 Years (pgs. 31-32). Oxford University Press.
(b) Stenger, Victor J. (2013). God and the Atom: from Democritus to the Higgs Boson: the Story of a Triumphant Idea. Prometheus Books.
2. (a) Laertius, Diogenes. (c.230). Lives and Opinions of Eminent Philosophers (TOC) (txt). Publisher.
(b) Lives and Opinions of Eminent Philosophers – Wikipedia.
(c) Lives of Eminent Philosophers – Wikisource.
(d) Monad (philosophy) – Wikipedia.
3. Taylor, Christopher. (1999). The Atomists, Leucippus and Democritus: Fragments: a Text with Translation with Commentary (pg. 158). University of Toronto Press.

Further reading

● Laertius, Diogenes. (c.230). Lives and Opinions of Eminent Philosophers (TOC) (txt) (WS). Publisher.
● Laertius, Diogenes. (c.230). Lives of Eminent Philosophers (translator: Pamela Mensche; editor: James Miller) (Amz). Publisher, 2018.

External links
Diogenes Laertius – Wikipedia.

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