The Late Hellenistic Jewish philosopher Philo of Alexandria has been neglected in studies of theories of mind and language in Post-Aristotelian Philosophy. Philo's dualism distinguishes immateriality and materiality in our language (logos). His arguments about the nature of mind and his explanations of the relation of speech to the mind, divine or human, draw heavily from Stoics and Platonists. Philo appears to present contemporary Platonist, anti-Stoic arguments that mind is of a different nature than body. Also, Philo deserves credit as our first detailed, surviving expositor of the view that meanings are thoughts, presented to the world in speech.