Plants and all animals may be intelligent in the sense that they can solve problems, but that's different from having explicit understanding of what they're doing. For that you need not a big brain (the overall size isn't what's important), but a part of the brain for processing higher-order thoughts. That's the neocortex, which women have as well as men.
Indeed, I've studied philosophy, not animals directly. Animal lovers, though, should be thankful that most animals lack the cognitive ability to experience the existential woes, to feel lost in an absurd universe. Not just philosophy but the neocortex is responsible for that higher form of suffering.
Animals can feel pain and some can feel loneliness and even shame, but very few species appreciate the existential stakes in the evolution of life or entertain the doubt that life has no valid meaning. Most species just get on with solving the problems that pertain to their biological life cycle. They're not preoccupied with any search for meaning, because they're unable to think about their thoughts. They lack the debilitating form of self-awareness that can cripple a person and make their species a world-threatening class of super-predators.
So I agree that there's a danger of getting lost in thoughts and philosophy. We should admire most animals for being immune to any such danger.