Philosophy

It is hardly a novel to suggest that peoples perceptions differ.  The more interesting questions pertain to how perceptions arise in the human mind and whether these perceptions accurately reflect the sources from which they arise.  Such were some of the questions addressed by John Locke in his seminal work An Essay on Human Understanding.  Although there has been disagreement about some of Lockes distinctions between primary qualities and secondary qualities, this paper will argue that his fundamental points were logical and have been born out in the form of modern scientific approaches in such fields as genetic engineering.  In support of this thesis, that Lockes distinctions were valid, this paper will discuss his strongest arguments and illustrations and demonstrate how modern scientific discoveries refute critics of his theory.
    Locke supports his assertion that the ideas which arise in the human mind do not match objects in the physical world through the use of several examples.  His strongest example, and one which seems to have been born out to a substantial extant in the modern field of genetic engineering, involves nothing more than a single grain of wheat.  Locke argued that there were primary qualities in the actual world and that these primary qualities were characterized by such physical phenomenon as  Qualities thus considered in bodies are, First, such as are utterly inseparable from the body, in what estate soever it be such as, in all the alterations and changes it suffers, all the force can be used upon it, it constantly keeps.
These qualities could not be altered by outside forces.  They would persist despite efforts to change them.  Using the grain of wheat example, Locke identified certain primary qualities such as solidity, extension, figure, and mobility.

  No matter how many times the grain of wheat was divided, in Lockes view, these primary qualities would remain.  These are internal qualities, integral physical features or properties of the object known as a grain of wheat, and the inability to alter or change these fundamental qualities therefore makes them of a primary or true nature.  Even if the grain is separated into what he refers to as separate and independent masses, the new masses created as a result of the division are still composed or constructed of the same primary qualities or physical features.  Those qualities are part and parcel of the objects natural design.  This philosophical premise, that primary qualities cannot be altered through a physical division, will be used later in this paper to refute suggestions that modern scientific advances in genetic engineering constitute an alteration of primary qualities quite the contrary, modern genetic engineering techniques confirm rather than refute Lockes theory and the grain of wheat example is the critical logical linchpin.

    It is first necessary, in order to properly create the analytical framework under which Locke examined human knowledge of the physical world, to discuss how he developed the concept of secondary qualities in order to distinguish the truth of physical objects from the deceptive ways in which the human mind created mental images in order to interpret or attempt to perceive the natural world.  In the same way that Locke illustrated primary qualities through the immutability of a grain of wheat, he illustrated secondary qualities most persuasively through how the mind constructs an intermediary mental image which then allows the mind to perceive what it classifies as a hot or a cold sensation.  Secondary qualities are therefore filtered through the human senses and the mental image that arises in the human mind is not a precisely accurate representation of the object being observed.  Again, rather than using a difficult example, Locke uses a common object in the form of water.  He makes his point by asking why when two hands are placed in water the different hands may sense hot and cold in different ways.  As with the grain of wheat the primary qualities are constant and, yet,  the human mind perceives the water differently through the sensory inputs, the sensory processing that aids in the construction of an intermediary mental image, and then a classification arises that associated with human perception.  These secondary qualities are variable this variability, in turn, convinces Locke that how humans ultimately perceive qualities such as color, smell, or touch does not match the reality of the object.  Secondary qualities are therefore impressions that are produced in the human mind.  In the example of the hot and cold water, for example, Locke observes that  the same water may at the same time produce the sensation of heat in one hand, and cold in the other which yet figure never does, that never producing the idea of a square by one hand which has produced the idea of a globe by another.

Locke thereby creates a theory which attempts to explain the unity of the natural world or the physical universe and the variability of human perception.  This has serious implications for human knowledge because it suggests that the illusions of the human mind must be better understood and overcome if an accurate knowledge of the underlying world is ever to be determined.

    Some critics might argue that modern scientific advances have finally refuted Lockes theories about the physical world and human knowledge.  It might be argued, for example, that scientists have learned how to manipulate the laws of the physical world in order to generate different realities.  A woman can use dye to change her hair from white to brown.  Japanese scientists can rearrange or otherwise manipulate genes in order to create orchids and flowers with different colors.  The logical mistake that these critics make, however, is in failing to think of Lockes grain of wheat and water examples.  In both of the aforementioned examples, colors would seem to change indeed, colors are perceived differently by the human mind.  But the underlying nature of the female hair that has been superficially dyed and the  underlying nature of the genetic composition of the orchid that has been genetically engineered have not been altered or changed.  The physical qualities of the hair remain the same and the physical qualities of the genes remain the same.  In the latter case, the genes have been rearranged or paired in different ways rather than altered at a core or root level.  Science has manipulated sensory perception rather than the internal composition of the physical objects if one were to alter, for example, the internal composition of the objects being perceived then the womans hair might turn to cabbage and the orchid to a rose.  That these fundamental alterations have not occurred lends credence to Lockes distinctions and in this authors view confirms them.

    In the final analysis, virtually everyone agrees that humans perceive things differently.  Humans have variable types of perceptions and it is how and why these perceptions differ that has generated so much inquiry and debate.  Lockes analytical framework, distinguishing between primary and secondary qualities, would seem to be logically sound and substantiated even in the face of modern scientific achievements.  Human understanding and knowledge of the physical world in which they live therefore remains imperfect.