Full Idea
It appears probable that the brutes have souls, though they are without consciousness.
Gist of Idea
It seems probable that animals have souls, but not consciousness
Source
Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1686.12.08)
Book Reference
Leibniz,Gottfried: 'Philosophical Writings', ed/tr. Parkinson,G.H.R. [Dent 1973], p.65
A Reaction
This will be a response to Descartes, who allowed animals sensations, but not minds or souls. Personally I cannot make head or tail of Leibniz's claim. What makes it "apparent" to him?