Full Idea
Cleanthes tried to prove the existence of God, arguing that the ascending scale of living creatures requires there to be a perfect being.
Gist of Idea
The ascending scale of living creatures requires a perfect being
Source
report of Cleanthes (fragments/reports [c.270 BCE]) by Teun L. Tieleman - Cleanthes
Book Reference
'Encyclopedia of Classical Philosophy', ed/tr. Zeyl,Donald J. [Fitzroy Dearborn 1997], p.145
A Reaction
Not a very good argument. Even if you accept its basic claim, it is not clear what has to exist. A perfect tree? If the being transcends the physical (in order to achieve perfection), does it cease to be a 'being'?