Full Idea
The sequences of the brutes are but a shadow of reasoning, that is to say, they are but connexions of imagination, transitions from one image to another.
Gist of Idea
Animal thought is a shadow of reasoning, connecting sequences of images by imagination
Source
Gottfried Leibniz (New Essays on Human Understanding [1704], Pref)
Book Reference
Leibniz,Gottfried: 'Philosophical Writings', ed/tr. Parkinson,G.H.R. [Dent 1973], p.152
A Reaction
This account of animal thought cannot capture the fact that they are motivated by their images, and obviously make decisions based on them. Externally, there is usually an obvious reason why even an insect does something.