Berkeley’s Objections In his book An Essay Concerning Human Understanding, philosopher John Locke suggested that all objects have primary and secondary qualities. Essentially, he defines primary properties as the ‘real’ properties of the object. These are contrasted against secondary properties, which Locke defined as nothing in the objects themselves but powers to produce various sensations in us. While Locke’s theories have largely held up to criticism through the years, not everyone has agreed with him. Berkeley, for instance, has several objections. In his 15 principles, for example, Berkeley questions Locke’s originating premise regarding primary properties and In his second Principle, Berkeley claims that objects must be perceived in order to exist, for the existence of an idea consists in being perceived (Berkeley 461). He bases this premise on the evidence that thoughts, passions and imaginative ideas cannot exist without a mind capable of perceiving them. And (to me) it seems no less evident that the various sensations or ideas imprinted on the sense, however blended or combined together (that is, whatever objects they compose), cannot exist otherwise than in a mind perceiving them (471). This goes directly against Locke’s concept of primary properties which are described as properties of an object that are true regardless of who perceives them or even whether they are perceived. Examples of primary properties include the object’s solidity, its figure, its relative motion to its surroundings and its quantity. In the example of a table, primary properties might include its hard surface and open area between the legs, its flat surface and height from the ground, its motionless status within the room and its singular status as an object. While Locke says that these things exist whether or not anyone perceives them, Berkeley suggests that none of these elements of the object can be true without someone first perceiving that they’re true. In this, he essentially applies Locke’s concepts of secondary properties to the entire object, eliminating primary properties. In truth, the object and the sensation are the same thing and cannot therefore be abstracted from each other (471). Another area in which Berkeley disagrees with Locke is in the characterization of our understanding. Locke indicates that our perceptions and experiences of the world are learned and shaped by our experiences of innate things that exist in the material world independently of perception while Berkeley argues that this cannot be so. It is evident from what we have already shown that extension, figure and motion are only ideas existing in the mind, and that an idea can be like nothing but another idea, and that consequently neither they nor their archetypes can exist in an unperceiving substance (472). He proves his point by starting with the secondary properties acknowledged by Locke to be ‘imaginary’ or existing only in the mind. These would include elements such as color, sound, temperature, smell or taste. Because he cannot conceive of an object in form or motion without also conceiving of it in color, smell or taste, Berkeley suggests these sensations, too, are little more than sensations and cannot be considered as being anything else but ideas in the mind.