One of the things I noticed when taking my Philosophy undergrad was how 17th century Philosophers (and Philosophers of other periods too) often made grandiose claims about how people thought about the world. Often their 100% certain proclamations were refuted by other Philosophers who were also 100% certain about how the world worked. A particular example of this would be the general commitment to the Platonic notion of how we are born with a complete set of concepts (believed and accepted by most philosophers prior to Locke), and then the commitment to the complete opposite, the ‘blank slate’ (Locke’s tabula rasa), the idea that we are born with zero ideas. Turns out that biology is more complex than that. Philosophy of Mind makes slow progress.