Now don’t tune out when I bring up this old question. Although you have probably heard it before, the answer may still surprise you.  Okay, if a tree falls in the forest and there is no one there to hear it, does it make any sound? I’ll just tell you right up front, the answer is no, it doesn't.        

Although I studied some physics in college, and a little anatomy here and there as well, I had never thought seriously about this question, and had assumed it was just silly. Of course the tree makes a sound! What difference does it make if someone is there or not? Then I read an article by Drs. Leonard Brand and Ernest Schwab, biology and anatomy professors, respectively, at Loma Linda University in Southern California. The article is titled “The Rainbow is All in Your Head,” and it appeared recently in a periodical called Dialogue (though this article hasn't been posted on the website yet, you can check out the magazine online at http://dialogue.adventist.org/indexes/essays.htm).         

It turns out I already knew most of the separate pieces of information needed to figure this out; I just had not put the information together in a way that yielded the answer to the question. Oh, you don’t believe my answer is correct? Well then listen to this, and you are likely to change your mind too.

An 11-foot-in-diameter coast redwood went down during an extended rainstorm in Northern California’s Montgomery Woods about three years ago. Not long after the storm, I went hiking in the woods and came upon the fallen giant. Let’s imagine what that event was like. The huge tree—maybe 275 feet tall—slowly begins to tip. The earth starts to crack open on one side; rivulets of water run into the cracks; small roots snap, then larger ones pop. As the tipping tree picks up momentum, the sodden earth beneath it begins to liquefy, further accelerating the fall. The tree smashes into two nearby redwoods, snapping limbs the size of telephone poles.  The limbs crash to the ground. The falling tree skids along the side of one of the trees, shearing off sheets of bark. Finally the redwood slams into the earth with an impact so violent the massive trunk breaks open, its heart shattered into shards the size of canoes.          

All that activity creates compression waves that move outward at a constant speed in all directions through the air molecules. If no one is there, that’s it. As the compression waves move outward they dissipate until, many miles away, the air molecules are not disturbed at all. In all of this, nothing has happened except that air molecules moved.     

But if someone is there, the fun is just beginning. The compression waves created by all this activity move out away from the tree until the molecules of air near the person’s ear drum start vibrating. As the air molecules bang into the eardrum like tiny little mallets, the eardrum begins to vibrate. This vibration is transferred to the inner ear, which includes many tiny receptors designed to respond to vibration—some respond to high frequencies, others to low. Each receptor is connected by a specific nerve to a specific spot in the brain. That spot in the brain is programmed to create a sensation that the person perceives as a specific sound. If the eardrum is soft and pliable, it transfers a very rich and sophisticated series of vibrations to the inner ear, which transmits a very large number of electrical impulses along many nerve pathways to the brain. The brain’s software, in turn, takes those electrical impulses and creates the wild array of sensations that a person would experience audibly as a huge redwood tree falling to the ground in a forest.          

Now imagine that those nerves connected to the inner ear could be unplugged from the brain like disconnecting your toaster from the wall. That person could be standing right next to the tree. There would be no sound, because the sound is created by the brain inside the person’s skull—nowhere else. Until it gets there, it is nothing but compression waves and electrical impulses.         

Now, without my going into a lot of detail, you can probably imagine that I could also describe a vision system that transfers light rays of different frequencies through the cornea to receptors in the back of the eye connected to nerves that transmit electrical signals to a different part of the brain programmed to create the sensations a person experiences as vision.         

Okay, here’s another thought experiment, proposed by Drs. Brand and Schwab. Imagine that we unplug the vision nerves, and unplug the hearing nerves, and then switch them, plugging the vision nerves into the sockets for the hearing nerves and the hearing nerves into the sockets for the vision nerves. They all transmit simple electrical signals. There is no difference between the signals. The difference is only in the brain software that receives the signals. So now the electrical signals sent by the ear go to the part of the brain programmed for vision. Is it sound that is produced? No, because it is the brain's vision center that is stimulated. The result must be something to do with sight, not sound. So you can see these signals cannot actually be considered sound until they get to the brain, because until that point, they could, theoretically, be turned into something other than sound. Of course, it is our good fortune that we can't go messing around like that with our brain circuitry. When our ears send electrical impulses through the nerves to the brain, those signals go directly to the correct brain software and it produces sound. We hear the tree fall.

Now step back in your mind from these kind-of-crazy mental experiments about brain circuitry, and think about this very real, highly sophisticated equipment in your body—the eardrums, receptors of the inner ear, auditory nerves, and the brain with its specialized software—all working in unison in response to vibrating air molecules to create sound. I have to ask, does all of this make you think there might have been a Designer involved with the development of those systems? Don’t you have to wonder, along with Moses, “Is he not your Father, your Creator, who made you and formed you?” (Deuteronomy 32:6, NIV).         

B.W.