Arthur Collier (1680–1732)

Clavis Universalis - the Universal Key, is an early 18th century work in support of the Subjective Idealist philosophy, the philosophy that the objects of our perception are just sensations received by the mind, and do not posses external existence.
To prove this point, that an object that we perceive is in existence internal, and cannot be held to have any necessary external existence, several practical and thought experiments are presented. This part of the book is interesting in that it does demonstrate that what we see cannot be taken for granted to exist externally. However, though Collier does do this successfully, what he fails to conceive is more important, and is probably what leads him into the trap of trying to prove the external world doesn't exist, his failure to make the distinction between the act of perceiving and the object perceived – that the object we see internally is an indirect representation of an external object. For example, his practical experiment using a mirror to duplicate the image of an object, he suggests to us appears to duplicate the object, which he rightly claims to be ridiculous, but somehow resolves by denying the existence of either object. And though this idea that an object cannot be see indirectly is absent from Colliers philosophy, it has been accepted by other less extremist Idealist philosophers such as Berkeley and Kant, the former allowing that the objects of our imagination are ideas of the object and exist as ideas only and not reliant on matter, and the latter claiming that the idealist does not have to deny the externality of objects, but must only deny direct perception of them.
To fill in the gap now created by Collier, to explain where our internal perceptions come from, he now introduces the idea that they are provided directly to us by God, alleviating any reliance in his system for external matter. This is a conclusion that Berkeley also reaches.
To then back up this bold claim in the second part of the book, he furnishes us with proofs for the inexistence of the external world, chiefly by stating contradictory properties of matter which show it cannot exist, but which are easily solved by finding one or other of his suppositions to be false.
The book concludes with a short section on the implications of his findings, in which he uses his philosophy of the nature of the universe to refute the Catholic belief in transubstantiation, it being in his interest as a member of an opposing denomination, and religious tensions being what they were at that time. This, it comes across, is the only reason he went to the trouble of writing this book, which in poor philosophical practice makes use of other theological assumptions to support its arguments, perhaps another reason this author remains obscure.… (más)