I don't know about monkeys, but to a far lesser extent than humans, I believe exiled chimpanzees must philosophise.
I came across the notion during research of the evolution of shamanic technology; shamanism, being a precursor to animism and religion might be evident in animal behaviours e.g. use of entheogens, totemism, social distinctions. If an IQ measure included 'wisdom' and we could pass the language barrier...