Philosophy of Mind came into its most compelling forms during the age of modern philosophy beginning with René Descartes. Perhaps infamously, Descartes claimed that mind and body are two distinct substances – philosophical jargon for what exists without the aid of any other thing. For Descartes, the world was clearly and distinctly physical in one sense and entirely mental in another. This seems perplexing, and Descartes did concede that the mind and body were closely intertwined and appeared to act with respect to one another, but his arguments clearly press that they are not causally connected in any way. These notions of dualism seem nearly preposterous with the advent of modern science, but were nonetheless important in developing our thought about the mind in the modern era.
Dualism gave rise to other interesting, yet now strongly refuted movements. One of these was idealism, or the doctrine argued famously by George Berkeley that states that all that exists are either ‘ideas’ or minds that perceive them. In this sense, an idea is defined as that which is perceived, inclusive of information imprinted on the senses, passions and operations of the mind, and conceptions formed by imagination and memory. Importantly, Berkeley argues that these ideas exist ‘in the mind’ exclusively: that is, they are purely mental and all things are simply combinations and aggregations of ideas. These immaterial ‘ideas’ then, are the only objects of human knowledge under idealism, and this theory denies the existence of physical objects entirely! The notion seems preposterous, but there is a very interesting argument found within idealism that can throw our conception of perception for quite the proverbial loop. More