In an apparent response to Descartes" work, John Locke wrote a series of considerations concerning how we perceive the nature of our world. In Descartes" fifth mediation, he discusses the nature of an object, and the properties that it can posses. From Descartes" arguments, it seems that he is trying to form the bulk of his argument to support a belief that objects in the physical world are the cause of most ideas, and there is a necessary link that must exist between the mind and the world that cannot be fooled. Locke looks at this argument in the following way. Looking at the world, he agrees with Descartes that objects do indeed create ideas and mental states in our minds. However, it is not just objects in the physical world that do this. Along with other internal mental stimulus, the lack of objects, or a part of an object can have the same effect on us. If one were to observe a wall with a crack in it, than a different belief about the state of the wall, and perhaps the whole building would be formed that if one saw a new, solid wall. This is known to Locke as Privation, or "the state of being deprived; especially: lack of what is needed for existence." The instance where there is a lack of a necessary object or part of an object can still cause all the mental states of a "real" object.
As one examines the property of an object it becomes apparent that any property that one observes can be organized into one of 3 categories: Primary, secondary, and powers of the third degree. Qualities of the first degree are such that they do not directly affect any of our senses. These are qualities like number, solidity, and motion. These qualities are of such that no matter the specifics of the arrangement of the object, it will always have those same qualities. If one quality is to be changed by force, than all the rest have to be the same. Whether a ball is rolling or not, there is still only one, solid ball.
