The Porphyrian tree, Tree of Porphyry or Arbor Porphyriana is a classic device for illustrating what is also called a "scale of being". It was suggested—if not first, then most famously in the European philosophical tradition—by the 3rd century CE Greek neoplatonist philosopher and logician Porphyry. It is also known as scala praedicamentalis.
Porphyry suggests the Porphyrian tree in his introduction (in Greek, "Isagoge") to Aristotle's Categories. Porphyry presented Aristotle's classification of categories in a way that was later adopted into tree-like diagrams of dichotomous divisions, which indicate that a species is defined by a genus and a differentia and that this logical process continues until the lowest species is reached, which can no longer be so defined. No illustrations or diagrams occur in editions of Porphyry's original work. But, diagrams were eventually made, and became associated with the scheme that Porphyry describes, following Aristotle.
Porphyry's Isagoge was originally written in Greek, but was translated into Latin in the early 6th century CE by Boethius. Boethius's translation became the standard philosophical logic textbook in the Middle Ages. Until the late 19th century, it was still being taught to students of logic.
The following very helpful passage by philosopher James Franklin gives some hint as to the history of the Porphyrian tree: In medieval education, the standard introduction to Aristotle's works was via Porphyry . . . more