The confusion which ties Ryle so closely to Descartes arises from a confusing mix of metaphors; Descartes and his contemporaries conceptualized of the mind as a thing of physical (if inconceivable) proportions, which allowed for a differentiation between "inner" and "outer" sense.
Ryle's close association with Descartes stems from an ambiguous blend of metaphorical language; both Descartes and their contemporaries conceptualized the mind in terms of physical (yet incomprehensible) size, allowing for a separation between "internal" and "external" perceptions.