Full Idea
We will not seek for the reason of natural things from the end which God or nature has set before him in their creation
Gist of Idea
We will not try to understand natural or divine ends, or final causes
Source
René Descartes (Principles of Philosophy [1646], §28)
Book Reference
Descartes,René: 'Philosophical Essays and Correspondence', ed/tr. Ariew,Roger [Hackett 2000], p.238
A Reaction
Teleology is more relevant to biology than to the other sciences, and it is hard to understand an eye without a notion of 'what it is for'. Planetary motion reveals nothing about purposes. If you demand a purpose, it becomes more baffling.