THE CONTENTS OF OUR IDEAS OF MODES
§1 . Having dealt in our last chapter with Locke's general theory of the origin of our ideas in the simple contents of Sensation and Reflection, and the formation of complex ideas from these elements, we must now proceed to examine, in more detail, his treatment of some of the more important ideas which enter into the constitution of our knowledge. In doing so, it will not be possible to separate completely the point of view of content from that of origin and manner of formation, with which, as we have seen, it is so intimately united in his thought. Indeed, it is precisely in the attempt to apply to some of our most fundamental conceptions the principle that the positive content of all our ideas must be drawn from experience, that what is primarily a descriptive survey of ideas tends to pass over into a criticism of the current categories.
The predominantly objective and logical point of view, from which the investigation of ideas is undertaken, shows itself in the classification of complex ideas, which forms the framework of the greater part of the Second Book of the Essay. Instead of a division based upon the diverse mental operations involved in their formation, complex ideas are divided according to the nature of the content apprehended, into ideas of modes, substances and relations. Ideas of modes are defined as 'such