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Note to Thomists: The Ear Is a Reverse Piano

Michael Egnor

Reverse Piano

As a student of St. Thomas, I am perplexed by the rejection of ID by some Thomists. While many Thomists endorse ID as good science in the mold of St. Thomas’ natural philosophy, some Thomists are quite hostile to ID. 

Some of the reasons for the hostility are valid: If we approach ID from a mechanical philosophy perspective — from the belief that the universe is actually, and not just metaphorically, a big machine — then we make a serious metaphysical error. A machine is an artifact whose components have no natural tendency to purposefully interact. The misunderstanding that nature is actually a machine is not, however, an inference from ID, but rather an inference from mechanical philosophy which is implicitly or explicitly held by some proponents of ID. That is a metaphysical error, not a scientific one. And ID is science, not metaphysics. 

ID is entirely consistent with Thomism. ID as a scientific theory can be stated simply: Some aspects of nature are best understood as analogous to designed artifacts. 

An Analogy to Machines

Nature is replete with systems that are best understood scientifically as analogous to machines. DNA replication and transcription, the translation of the genetic code into proteins, cellular energy metabolism, the flagellum, the eye, and countless other biological structures and processes are best understood scientifically as if they were designed. ID is heuristic. 

To that point, Scientific American has just published a remarkable (unintentional) endorsement of ID science:

There’s an “Inverse Piano” in Your Head: A Kavli Prize-winning scientist details the magic of transforming vibrations into sound in the inner ear

“I think we as scientists tend to underemphasize the aesthetic aspect of science,” … says [neuroscientist James Hudspeth]. “Yes, science is the disinterested investigation into the nature of things. But it is more like art than not. It’s something that one does for the beauty of it, and in the hope of understanding what has heretofore been hidden. Here’s something incredibly beautiful, like the inner ear, performing a really remarkable function. How can that be? How does it do it?”

Hudspeth, of Rockefeller University, just won the Norwegian Academy of Science’s Kavli Prize in science, which carries a million-dollar stipend. 

Hudspeth:

In the 19th century there was one really important physiological insight from the German scientist Hermann von Hemholtz that endures today. He recognized that the cochlea — the receptive organ of the ear — is, in essence, an inverse piano. In the piano, each of the strings represents a single tone and the output is stirred together into a harmonious whole. The ear basically undoes that work. It takes the harmonious whole, separates out the individual tones and represents each of them at a different position along the spiral cochlea. Each of the 16,000 hair cells that line the cochlea is a receptor that responds to a specific frequency. And those hair cells are in a systematic order, just as the piano strings are…

The common currency of the nervous system is electrical. It is action potentials — streams of 1’s and 0’s, in effect — much like those in a computer. But the currency of the external sensory world is very different. We have photons — that is sight. We have pressure — that is touch. We have molecules — that is smell or taste. And finally we have vibrations in the air — that is the essence of sound. Each of those different types of physical stimulus must somehow be converted into the electrical signals that the brain is then capable of interpreting. That’s the transduction process. The thing that motivated me, and took the first 20 years of my 40-year career to really understand, is how that is accomplished. How the mechanical vibration, as it strikes the upper part of the hair cell — the so-called hair bundle — how that energy is converted into an electrical response.

Hudspeth spent the first half of his scientific career studying the cochlea as an harmonic analyzer — a machine invented in the 19th century to analyze the Fourier components of a signal. Each of the hair cells in the inner ear vibrates at a specific frequency, and the inner ear is thus able to tease out the Fourier components — the individual sine waves — of sound entering the ear. Harmonic analysis today (performed on computers) is a cornerstone of science across many disciplines. Remarkably, it is also how the inner ear allows us to perceive sound. 

Hudspeth:

The second half of my career was unexpected. It became apparent — from a number of lines of study by myself and others during the first 20 years — that the system was not just a passive transducer. The sound going in didn’t simply evoke a response. Instead, the ear has a so-called active process. The ear has a built-in amplifier, and that amplifier is unlike any of our other senses. It would be as if light going into the eye produced more light inside the eye, or smell going into the nose produced more smell molecules. In the case of our ears, the sound that goes into the ear is actually mechanically amplified by the ear, and the amplification is between 100- and 1,000-fold. It’s quite profound. And the active process also sharpens the tuning of hearing, so that we can distinguish frequencies that are only about 0.1 percent apart. By comparison, two keys on a piano are 6 percent apart.

Hudspeth’s understanding of the design of the inner ear has major medical applications:

One of the biggest challenges in the field is that hair cells in mammals are not replaced when they die. That is why all of us tend to get progressively harder and harder of hearing, and eventually significantly deaf. One of the approaches we’re taking is to screen drugs to try to find a molecule that will allow hair cells to begin to regenerate again. We’ve screened 80,000 drugs so far and we have two compounds in particular that look promising. We’re now trying to learn in more detail how they operate, and whether they or related compounds could be used for regeneration in humans.

An Inference to Design

The inference to design is essential to Hudspeth’s work. A piano takes the sum of individual notes (vibrating strings) excited by keys and produces a symphony. The inner ear does just the opposite. The inner ear takes the symphony and decomposes it into individual notes, using the sensitivity to vibrations of hair cells in the cochlea. The inner ear is a reverse piano. This insight is design science applied to biology. If you know nothing of the design of harmonic analyzers, you can’t understand how the inner ear works.

There is obviously no Darwinian explanation sufficient to this astonishingly elegant system. It’s beyond even the most fanciful just-so stories. Darwinists don’t even try to explain it. They just hope you won’t notice. 

And the reverse-piano harmonic analyzer of the inner ear is obviously best understood as a type of design, using “design” analogically, not univocally. 

This analogy between artifacts and nature was endorsed by an early proponent of intelligent design:

For an artificer produces a determinate form in matter by reason of the exemplar before him, whether it is the exemplar beheld externally, or in the exemplar interiorly conceived in the mind… in the divine wisdom are the types of all things… in things created one may be called the exemplar of another… by the analogy of some kind of imitation. 

This of course is St. Thomas (ST I,Q.44,art3), who explicitly uses the analogy to an artificer to explain forms in creation. 

The inner ear can only be understood by analogy to a harmonic analyzer. It can only be understood with recourse to design science. ID is a cornerstone of science, and is quite consistent with Thomism, when the design is understood analogically, as nearly all ID scientists do. 

It’s time for Thomists to acknowledge the heuristic power of design science, and its compatibility with Thomistic metaphysics.  

Photo credit: Attiesocialmedia [CC BY-SA 4.0], from Wikimedia Commons.