Published in 1669, John Locke’s An Essay Concerning Human Understanding is the foundational text for modern philosophical empiricism. This essay set the standard for empirically-based arguments against the traditions of rationalism. Locke puts forth the underlying premise that simple ideas are created through experience, while more complex ideas are created by the mind as it integrates these simple ideas into more complex concepts.
The Essay also differentiates between the primary qualities of objects and the second quality of objects. Primary qualities are inherent within the object and remain fixed and not subject to perception. The secondary qualities are those aspects which originate within the observer and are subject to changes in perception. While significant as part of Locke’s modernization of empirical thought, the central issue that An Essay Concerning Human Understanding seeks to contest is the establishment and widespread acceptance of the existence of innate ideas.
The existence of innate ideas, which are already in place at birth, was fundamental to the logic of Cartesian rationalism. This logic proposed the existence of ideas which exist independent of both perception and experience. Therefore, they had to be considered essential and universal truths that could only exist by virtue of agency the individual mind on which they were imprinted. Since innate knowledge could not be gained through perception or experience, the only logical conclusion to explain their existence was they were put there by a perfect supreme creator.
Locke’s essay raises objections to the fundamental reasoning of the existence of innate ideas through rational analysis based on empirical evidence. The central symbol in the essay to describe how knowledge is acquired is the “tabula rasa” or blank slate that exists at birth. Only through experience can knowledge be written upon that slate. The systematic undermining of the theory of innate ideas first targeted the weakest pillar of its support: it must be true because there is universal agreement that it must be true. Locke response to this unsound support was to observer that “this argument of universal consent, which is made use of to prove innate principles, seems to me a demonstration that there are none such; because there are none to which all mankind give a universal assent.” The investment of belief in an idea partly on the basis that it is universally accepted as true actually seems antithetical to the underlying skepticism of rationalist philosophers toward in trusting any and all received perceptions as true; Locke uses the revelation of this contradiction as the wrecking ball which proceeds to demolish belief in the existence of innate ideas.
An Essay Concerning Human Understanding proceeds from this point toward a methodical dismantling of the principle of non-experiential knowledge using the most basic of empirical evidence. How can ideas like a circle being round and that 2 plus 2 equals four be considered innate, his essay, asks, when every child must be taught these thing before understanding them? Furthermore, what of those individuals who are incapable of ever understanding such simple concepts despite supposedly being born with them already in place?
In fact, An Essay Concerning Human Understanding brings empirical philosophy into the modern world, where it can influence every discipline from history to scientific experimentation. The historical context within which Locke composed the essay endowed its epistemological issues with a more immediately political dimension. The rough treatment directed toward contesting the widespread belief in innate ideas was manifested in part as an attack upon the power and authority of its most fervent proponents. These proponents were political and religious figures exploiting universal agreement on the existence of innate ideas maintain and manipulate the faith of the masses who had been conditioned to believe that the opinions of those in power were absolute facts.