Nature of Thought Is One

¶ … nature of thought is one of the oldest and most debated philosophical questions. Because no philosophy can exist without thought, the question of how thinking and ideas occur could be considered one of the paramount questions of human understanding. To have an idea of how ideas work is essential for an examination of truth, reality, and even perhaps the existence (or non-existence) of God. Conversely, these things can all play an important role in developing an explanation for how thought and ideas work. Yet for all the importance of understanding hw and why thought works, and the importance of many related philosophical and even practical questions, this issue is still very much a matter of debate. Perhaps at no time in the history of philosophy, however, was the debate ever so full explored as in the eighteenth century, when three British philosophers advanced their theories regarding human thought.

The first of these actually appeared ten years before the dawn of the 1700s. John Locke's an Essay Concerning Human Understanding advances one of his -- and philosophy's most famous theories, that of the tabula rasa or "blank slate." It was Locke's belief that all humans are born with their minds being just such a blank slate, without any ideas, prejudices, or beliefs. Ideas, Locke maintains, only come with experience; before thought there must be sensation. George Berkely, a contemporary of Locke's published his Treatise Concerning the Principles of Human Understanding twenty years later, and though he does not directly disagree with Locke in eah of his assertions, he does take thins a step further by insisting that the world itself is made up only of ideas -- a human idea, he argues, can only resemble other ideas, not physical objects. Scottish philosopher David Hume, in his 1748 work an Enquiry Concerning Human Understanding, agrees that sensation creates thought, but also describes how these thoughts can be manipulated.

All three of these men were working from the empiricist school; that is, each believed that only through sensation or perception could any thinking -- and thus any possible knowledge of truth -- occur (Hooker). This is opposed to the rationalist schools, which believes that perception will only lead to false ideas, and that true knowledge can only be achieved through reason (Stanford). Locke's Essay Concerning Human Understanding is in many ways a refutation of Descartes' rational views of the origin of truth and thought (Hooker). As he puts it, "I know it is a received doctrine, that men have native ideas, and original characters, stamped upon their minds in their very first being" (Locke, 121). He goes on to refute this claim by insisting that all thought originates as sensation: "Our observation employed either, about external sensible objects. Or about the internal operations of our minds perceived and reflected on by ourselves, is that which supplies our understandings with all the materials of thinking" (Locke, 122).

This explanation of thinking is not as complicated as it may appear at first glance. Basically, Locke is simply saying that we cannot have an idea of anything before we have experienced that thing. So in order to form an idea of yellow, soft, hard, bitter, or sweet, "they from external objects convey into the mind what produces there those perceptions" (Locke, 123). Furthermore, Locke breaks up thought into simple and complex ideas. According to him, simple ideas are "the materials of all our knowledge" -- things like the physical qualities mentioned above (Locke, 145). Once the mind has absorbed these simple ideas, however, it is able to manipulate them into more complex ideas, which are basically mixtures of simple ideas that have not been directly experienced. Locke then goes on to define and describe several types of simple ideas.

Complex ideas can also take several forms, according to Locke. First, there is the combining of simple ideas into one single complex idea, "and thus all complex ideas are made" (Locke, 213). Humans also have the ability to look at two ideas simultaneously without combining the; Locke calls these ideas of relations. Finally, abstraction occurs when ideas are separated form all other ideas that generally accompany them in experience. In this manner, Locke believes he has completely described and defined all types and aspects of human thought.

Berkeley, like Locke, believes that it is only through sensation or experience that we can attain any knowledge about the world around us. He goes somewhat further, however, in describing the way these sensations work, claiming that most ideas that Locke would have called "simple" are really complex lists of simple ideas combined into one larger idea -- the idea of an apple, for instance, is a combination of many different ideas regarding shape, color, taste, smell, etc. (Stanford). Berkeley also reverses, in a way, the argument made by Locke. Whereas Locke believes that the mind's ideas are shaped by -- indeed, are created by -- experience of things by the senses, Berkeley claims that the existence of these things is dependent on an observational mind: "That neither our thoughts, nor passions, nor ideas formed by the imagination, exist without the mind, is what everybody will allow. And it seems no less evident that the various sensations or ideas imprinted on the sense, however blended or combined together...cannot exist otherwise than in a mind perceiving them" (Berkeley, 30).