Concept
Species
Overview
one of the basic units of biological classification and a taxonomic rank
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
In the original texts
Passages from public-domain books where Species is discussed.
It need not be supposed that all varieties or incipient species attain the rank of species. They may become extinct, or they may endure as varieties for very long periods, as has been shown to be the case by Mr.
Charles Darwin, Darwinism stated by Darwin himself
names the idea; a chapter is titled for it; states what it is; opens on it
On the view that species are only strongly marked and permanent varieties, and that each species first existed as a variety, we can see why it is that no line of demarcation can be drawn between species, commonly supposed to have been produced by special acts of creation, and varieties which are acknowledged to have been produced by secondary laws. On this same view we can understand how it is that in a region where…
Charles Darwin, The Origin of Species by Means of Natural Selection
names the idea; states what it is; the book is about it; opens on it
The formation and maintenance of a species, considered as an assemblage of similar organisms, is interpretable in an analogous way. We have already seen that in so far as the members of a species are subject to different sets of incident forces, they are differentiated, or divided into varieties. And here it remains to add that in so far as they are subject to like sets of incident forces, they are integrated, or…
Herbert Spencer, First Principles
names the idea; states what it is; author linked in the graph; opens on it
For all such propositions have for their subject either the individual or the species. It is true that, inasmuch as primary substance is not predicable of anything, it can never form the predicate of any proposition. But of secondary substances, the species is predicated of the individual, the genus both of the species and of the individual. Similarly the differentiae are predicated of the species and of the…
Aristotle, The Categories
names the idea; states what it is; author linked in the graph
But diversity of species is always accompanied with a diversity of nature; thus in species of colors one is more perfect than another; and the same applies to other species, because differences which divide a genus are contrary to one another. Contraries, however, are compared to one another as the perfect to the imperfect, since the "principle of contrariety is habit, and privation thereof," as is written…
Aquinas Thomas, Summa Theologica, Part I
names the idea; states what it is; author linked in the graph; opens on it
Philosophers who discussed Species
- Pierre Louis Maupertuis
- Thomas Aquinas
- Herbert Spencer
- Speusippus
- James Burnett, Lord Monboddo
- J. L. Schellenberg
Related ideas
- Yale University Press
- Fossil
- Genetics
- Hierarchy
- Jean-Baptiste Lamarck
- Opposite
- Hylomorphism
- Philosophical Transactions of the Royal Society
- Organism
- Mutation
- Natural selection
- University of California Press
- Renaissance
- Philip Kitcher
- Scientific American
- On the Origin of Species
- The New York Times
- Aristotle
- Aristotelianism
- Eagle
- Property (philosophy)
- Carl Linnaeus
- MIT Press
- DNA
Opposing perspectives
Place in the tradition
Part of Philosophy of biology.