Species

The Classical Era: Science by Division 5

TERMS AND TRADITIONS
The modern and medieval word “species” is a Latin translation of the classical
Greek word eidos, sometimes translated as “idea” or “form.” Other significant
terms are also translations of Greek terms: genus from genos, differentia from
diaphora. Liddell and Scott tell us that eidos means “form” and is derived from
the root word “to see,” and genos means “kind” and is derived from the root
word “to be born of.”
We still find these senses in the English words “specify,” “special,” “spec-
tacle,” and “generation,” “gene,” and “genesis.” Diairesis or “division” is an
interesting term that will play a major role in our story. Another Greek term
that is later adopted by the Latins is synagoge, or in Latin, “relatum.” Relata are
those features by which things group together. Essentia, the Latin term used for
“essence,” is a neologism for a phrase used by Aristotle, the “what-it-is-to-be.”
The Latin term substantia is occasionally translated as “essence” in natural
historical works, but this is often misleading.

Greek Word,

Plural Form Classical Meaning Latin Translation English Words

eidos, eidē
εἲδός, εἰδή

That which is seen, form, shape,

figure; a class, kind, or sort

Species, forma Species, idea,
kind, sort
(Locke), form
genos, genē
γένος, γενή

Race, stock, family; a generation Genus (pl. genera) Genus, kind

diaphora
διαφορά

Difference, distinction, variance,

disagreement

Differentia

(pl. differentiae)

Difference

diairesis
διαίρεσις

A dividing, division Divisio Division

synagogē
συναγωγή

A bringing together; a conclusion Relatum

(pl. relata)

Relation,

affinity

See Liddell and Scott (1888). However, merely because words derive their

etymology from older terms, or translate words in other languages, it does not

immediately follow that they are the same terms with the same intension or

extension, or that one author is influenced by another. By eidos and species,

for example, different authors have meant forms, kinds, sorts, species in the

logical sense of non-predicables (Ross 1949, 57), biological species, classes,

individuals, and collections, both arbitrary and artificial, or natural and objec-

tive. In particular, species has meant both varieties of ideas and sense impres-

sions, species intelligibilis (Spruit 1994–1995), and also the material form of

the elements of the sacraments in the Roman Catholic tradition. This must be

borne in mind or it will cause confusion when we consider the views of differ-

ent authors. This is an instance of a more general problem, called “incommen-

surability” after Kuhn’s thesis that terms in scientific theories can have different