Introduction
Berkeley starts the book inquiring about the cause of Doubts and Difficulties, and proposes that it starts with the wrong use of our Faculties. He wants to discover the principles which introduced all the Doubtfulness and Uncertainty, to inquiry first principles of human knowledge. He examines the opinion that Mind has a power of framing Abstract Ideas or Notions of Things. Mind has the ability to separate out single abstract idea from all ideas mixed in the same Object. However, my imagination will not conceive the abstract idea without particulars. Here Berkeley refutes Locke’s opinion that the ability of getting abstract general ideas is tied to Language, and all Words must correspond to certain ideas, so the Words about general ideas corresponds to abstract general ideas, this is the classical conceptualist position. Berkeley’s position is a nominalist one, which says we don’t have a corresponding abstract general ideas for the general Words, whenever we think of general ideas, like Motion or Extension, we think of some particular motion with particular extension. The proposition involving general ideas just means it does not matter what particular Extension we think about, the proposition always hold true. Berkeley provides further arguments for the nominalist position by observing how Ideas become general. He is not denying there are general Ideas, but only that there are abstract general Ideas. An idea becomes general by representing all different ideas of the same sort. And for example Line becomes General, by being made a Sign of an abstract or general Line, and the name Line is also made General by being a Sign. And as the idea of general Line owes its generality to its being the Sign of an abstract or general Line, so the name Line must be thought to derive its Generality from the same Cause, namely the various particular Lines which it denotes.