The Damned Olde Man

Perception, Forests, Falling Trees, and the Question of Existence

“If a tree falls in the forest and no one is there to hear it, does it make a sound?” This age old philosophical question has recently come to be of interest to me. The answer is either “yes” or “no” so it may seem simple enough. But it is not the answer, but how one arrives at the answer that is intriguing.

At the very base of this question is the question of existence itself. How do we know we exist? Rene Descartes proposed perhaps the best answer to this that I have seen, “Cogito ergo sum” (I think, therefore, I am) (Newman, 2005). He questioned his own existence and concluded that the only thing he could know for certain was that he has thoughts, and that because of this, he can know that he exists. In other words, Descartes knows he exists because he can perceive himself.

Is perception necessary to prove existence? This is the question proposed by George Berkeley. And so we delve into the realm of the possibility of unperceived existence. If a tree falls in the forest and no one is there to hear it, does it make a sound? In other words, does it have substance? Aristotle believed that a substance is “that of which everything else is predicated, while it is itself not predicated of anything else” (Cohen, 2008). For Aristotle, the tree would have substance and its falling would make a sound.

But would Aristotle be correct? If the answer to this question is no, it does not make a sound, then one might call into question, the validity of the question itself. If existence is dependent upon perception, then the question is moot. If the sound did not exist because there was no one to perceive it, then the tree never fell, because neither it, nor the forest could exist either. If neither tree, nor forest exists, then the question cannot be asked. Therefore, to ask the question is to require an affirmative answer. Either Berkeley’s question cannot be asked, or Aristotle is correct by default.

The real question, then, is whether or not we ask the question. Or, we change the question to be asked. Is perception necessary for existence? Descartes perceived his own thoughts, and thus proved his existence. Can we know that we exist without relying upon perception? Can we know something that we have not perceived?

Let’s begin by exploring perception. Perception is the process of interaction with and interpretation of the environment (Sternberg, 2009). It involves a wide range of psychological phenomena. The human being has five basic senses, vision, hearing, touch, taste, and smell which are used to gather information about the environment. These senses send the input to the brain where it is processed and interpreted. The interpretation of this input is perception.

Memory is the ability to store, retain, and recall information and experience (Sternberg, 2009). It is stored perception. Once stored, a perception can then be considered knowledge and it can be manipulated and recalled. Epistemology poses three questions (Markie, 2004). How is knowledge acquired? What are its limits? What is its nature? The answers to these three questions can be found in the continuum between rationalism and empiricism.

Rationalists adopt one or more of the following three theses, intuition/deduction, innate knowledge, and innate concepts (Markie, 2004). Two other theses may or may not also adopted, indispensability of reason and superiority of reason. Empiricists use the thesis that there is no source of knowledge other than experience (perception). Thus the debate is over innate knowledge vs. acquired knowledge.

Let’s return to “cogito ergo sum.” Descartes perceived that he thought and knew he existed. But how did he know how to perceive? Perhaps Descartes asked the wrong question. Consider, for a moment, knowledge. If the empiricists are correct, all knowledge is derived from perception. If perception is the interpretation of sensory input, then if we do not already know how to interpret this input, we can perceive nothing. Therefore, the knowledge of how to perceive must be innate. If it weren’t, we could not know (nor could we learn) how to interpret incoming data, we could not then commit that data to memory, and there would be no knowledge to think about. If thought proves existence, perception proves innate knowledge. Without an innate knowledge of how to perceive, we could not think. Perception is Aristotle’s substance “of which everything else is predicated, while it is itself not predicated of anything else” (Cohen, 2008) and Descartes could have stated “Sentio ergo cogito ergo sum” (I perceive, therefore I think, therefore I am).

-TDOM

References

Cohen, S. M. (2008). Aristotle’s metaphisics. Retrieved May 19, 2010, from Stanford Encylopedia of Philosophy: http://plato.stanford.edu/entries/aristotle-metaphysics/

Markie, P. (2004). Rationalism vs. Empiricism. Retrieved May 13, 2010, from The Stanford Encyclopedia of Philosophy: http://plato.stanford.edu/archives/fall2004/entries/rationalism-empiricism/

Newman, L. (2005). Descartes Epistomolgy. Retrieved April 20, 2010, from Stanford Encyclopedia of Philosophy: http://plato.stanford.edu/entries/descartes-epistemology/#4.1

Sternberg, R. J. (2009). Cognitive Psychology. Belmont, Ca: Wadsworth, Cengage Learning.

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