Introduction
“If a tree falls in the forest and there is no one around to hear it, does it make a sound?” is a classical philosophical puzzle. It is sometimes attributed to George Berkeley; however, the philosopher did not discuss the question directly (Campbell, 2014). The puzzle concerns the nature of human understanding of the perceived world and whether or not the world can exist independently of human perception. As such, the question discusses the nature of human knowledge, understanding of the outside world, its existence, and its relation to human experience. These topics fall under the purview of epistemology, the branch of philosophy that is concerned with knowledge. The puzzle was formulated between the 17th and 18th centuries, when advances in science led to a renaissance of rationalism and thus, put the issues of objectivity of knowledge to the forefront of philosophical thought. It can be seen as a response to contemporary scholars such as René Descartes and John Locke.
Epistemology
Over the years, multiple interpretations of the puzzle have been proposed. In essence, they can be seen as contingent on the following two ideas, as explained by Campbell (2014). First, humans have knowledge of their surroundings because of sensory experience (Campbell, 2014). Second, the sensory experience can only grant knowledge of the sensory experience itself (Campbell, 2014). Combined, these ideas create an epistemological paradox: the only knowledge possible for the human mind is the knowledge of sensory experience (Campbell, 2014). Thus, the puzzle can be used as an illustration of epistemology in general: what is the real world, how do we know of it, and can it exist outside of our perception at all?
From these ideas, one can surmise that humans also have conceptions of objects that exist independently of the mind. However, these concepts can only be acquired through sensory experiences (Millar, 2016). The same sensory experiences allow one to conceive the object as possessing certain qualities, which also exist independent of perception. Furthermore, such conception includes a series of causal relationships; for instance, an object will still be in the place one left when one looks at it again (Millar, 2016). Leaving the object and finding it in the same spot are causally related: the object is there now because it was there when one put it there previously (Millar, 2016). This example illustrates a human understanding of the existence of continuity, maintaining the causal relationships between objects and events.
More practical explanations of the puzzle have been suggested, as well. For instance, one is concerned with the practical definition of sound: vibrations will only become sound when processed by the human ear (The Chautauquan, 1883). Therefore, the answer to the puzzle is negative as the presence of sound is contingent on human presence. This explanation is similar to one proposed by adherents of empiricism.
The puzzle, through its multiple interpretations, illustrates the core concerns of epistemology. First, it questions the nature, acquisition, and retaining of knowledge. It explores whether knowledge can be innate or has to be acquired through human perception. Second, through the relation of knowledge of perception, it questions whether events can exist outside of perception, or whether perception can exist independently of knowledge. Finally, by offering multiple possible interpretations, it illustrates several different views on epistemology.
John Locke’s Views
John Locke was a philosopher who died before the puzzle was formulated, or related questions were discussed by Berkeley. However, his views on the nature of reality and human perception of it allow for a different interpretation. The world, according to Locke and empiricists, exists independent of human perception. However, as no ideas or principles are innate, the world can only be understood through one’s natural faculties of perception (Locke, 1690). Perception, though not perfect, is merely the human way of experiencing the world. Although different people can perceive the same objects and events — causes — differently, they cannot perfectly communicate these ideas to others (Campbell, 2014). Therefore, using colors as an example, it is irrelevant that two people perceive yellow differently; so long as the two agree on which objects are yellow, it can be surmised that they perceive the objective reality (Campbell, 2014). Thus, an event can occur without being directly perceived and then surmised by observing its effects.
For Locke, perception is a mindful activity that cannot occur unconsciously. Only when the mind takes notice of a sensation and reflects upon it does perception occur (Locke, 1690). Furthermore, perception is altered by judgment or previous knowledge; for instance, a round object can first be perceived as a flat circle (Locke, 1690). Then, one’s judgment, previous knowledge of round objects and light will alter this perception into one of a convex object (Locke, 1690). Perception is, therefore, contingent not only on an event being observed by a sensory organ but also mindful reflection and judgment.
Locke further distinguishes qualities in objects that he identifies as primary and secondary. Primary qualities are innate properties of an object that remain regardless of human perception; these qualities include size, shape, and motion (Locke, 1690). Secondary qualities are affected by the perception of the object’s primary qualities; they include taste and sounds (Locke, 1690). Thus, sound can be viewed as a secondary quality of an object, the human perception of the motion of the object itself or air particles.
Based on these principles, Locke’s answer to the puzzle can be deduced as similar to the above practical interpretation. Since sound is a secondary quality created by perception, a falling tree will produce no sound by itself. It will have the primary quality of motion, and through it will impart motion on air particles. Only this motion can, in turn, be felt by the human ear and reflected in the mind as sound. It is through this secondary quality one can perceive the tree as falling. Furthermore, as perception is not unique to humans, a falling tree would produce a sound in an animal if one was nearby.
Conclusion
“If a tree falls in the forest and there is no one around to hear it, does it make a sound?” is a philosophical puzzle that serves as a strong illustration of epistemology as a field of philosophy. It draws attention to the core concerns of the field, such as the nature of reality, knowledge, its acquisition, and the relationships between reality, knowledge, and perception. Many branches of epistemology can be used to interpret the puzzle, yielding different highly illustrative answers. For instance, empiricism, represented by the philosopher John Locke, would argue that sound is a property of perception. Therefore, while the falling tree would enable an observer to perceive it through sound, it would not make the sound itself, merely the conditions for its motion to be perceived as sound.
References
Campbell, J., & Cassam, Q. (2014). Berkeley’s Puzzle: What does experience teach us? Oxford University Press.
The Chautauquan: Organ of the Chautauqua Literary and Scientific Circle. (1883). United States: M. Bailey.
Locke, J. (1690). An essay concerning humane understanding (Vol. 1). Project Gutenberg. Web.
Millar, A. (2016). Berkeley’s Puzzle. Analysis, anw070. Web.