Atheists and agnostics often ask me if I am willing to allow possible scientific discoveries to falsify my Christian faith. They ask me to specify a scientific discovery that, if proven true beyond any reasonable doubt, would cause me to publicly renounce Christianity and join the ranks of nontheists.

In such situations I am quick to provide examples if, for no other reason, than to give me an opportunity to reverse the question. Strategic examples allow me to ask the inquisitors if they would be willing to renounce their nontheistic beliefs and adopt Christianity in the face of scientific discoveries established beyond reasonable doubt. I try to choose examples where the converse establishes God's existence.

One such example is human exceptionalism: the idea that humans possess capabilities or characteristic features unique from all other species. If it were proven beyond reasonable doubt that humans differ only by degree from other species but not fundamentally in kind, that proof would refute a cornerstone of the Christian faith. The doctrine that humans alone, among Earth's life, are created in the image of God would be destroyed. Christianity would be falsified. On the other hand, if scientific research were to establish beyond reasonable doubt that humans indeed are exceptional, such research would falsify nontheistic belief systems and provide evidence beyond reasonable doubt that Christianity is true.

Human Speech Expression Complexity
Speech has long been recognized as evidence for human exceptionalism. Other animals certainly use sounds to communicate with one another. However, only humans are capable of developing and using languages with thousands of distinct words, complex grammatical systems, multiple verb tenses, a variety of word intonations, and symbolic systems for expressing language communication independent of sounds. Now a new research study adds to the weight of evidence for speech capability as one proof of human exceptionalism.1

Two Dutch linguists at the Max Planck Institute for Psycholinguistics, Hans Bosker and David Peeters, performed experiments on six sets of human volunteers. They designed the experiments to determine the degree to which hand gestures augment the efficiency and speed of vocal language communication between humans.

Bosker and Peeters noted that given the enormous vocabularies of human languages (English, Japanese, and Korean all have vocabulary sizes greater than 500,000 words), the sounds of spoken words can cause ambiguities in word recognition. For example, shifting the emphasis from OB-ject to ob-JECT makes an enormous difference in how one interprets the word object in a spoken sentence. As another example, where spoken speech is being delivered rapidly, a listener might not recognize the distinction between coat and code.

In the experiments, Bosker and Peeters asked volunteers to watch videos of speakers using varying degrees of hand beat gestures. The linguists observed that the volunteers were much more likely to hear emphasis on a syllable that coincided with a hand beat gesture and, hence, discern the correct meaning of the spoken word. This observation was not specific to a particular language. It appeared to "function as a language-universal prosodic cue."2

The researchers' experiments added to the weight of scientific evidence for the McGurk effect, that for humans visual input influences the perception of speech sounds. In a classic paper, Harry McGurk and John MacDonald demonstrated the important roles that mouth and lip movements play in the comprehension of speech.3 Head nods, eyebrow movements, and facial expressions also make significant contributions to speech comprehension.

In their paper, Bosker and Peeters noted that a wide range of hand gestures augment speech comprehension. An obvious one is the use of one's arm and finger to point to the object being addressed. Speakers also use their hands to mimic the shape or the action of an object, providing listeners with visual pictures of the mentioned object. The bottom line is that there is growing scientific evidence that language comprehension is a broad synthesis of the human senses and human anatomy.

Creation Implications
One reason why human speech communication is so powerful, complex, and efficient is that the human body is anatomically designed for optimal speech communication. The human lungs, larynx, pharynx, vocal cords, mouth, and lips are optimized for uttering a wide range of distinct sounds at a rapid pace. The human brain is designed for complex language capability and for multilingual capability. Human legs and feet are designed to set the arms and hands free from locomotion. Human arms and hands are capable of amazing dexterity and eye-hand coordination and rapid, repetitive movements. The eyes of humans with irises and pupils set against large white spheres (a feature not shared with nonhuman primates) permit signaling between humans over distances of many meters. The human face is capable of a wide range of expressions.

The human body is optimally designed for speech communication involving just a few people in a quiet setting. It also is optimally designed for what researchers call "cocktail party listening." Cocktail party listening refers to humans gathered in a crowded situation where many people are talking simultaneously in an environment where music and other background sounds interfere with speech recognition. Researchers have noted how well-designed human brains and human bodies are for selective listening.4

The range and extent of anatomical and neurological features that permit complex, efficient speech communication are unique to humans among life-forms. This research provides additional evidence for the biblical doctrine of human exceptionalism. In turn, the optimization of the anatomical and neurological features that permit complex, rapid, and energy-efficient speech communication provides additional evidence for supernatural, super-intelligent design.

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Endnotes

1. Hans Rutger Bosker and David Peeters, "Beat Gestures Influence Which Speech Sounds You Hear," Proceedings of the Royal Society B 288, no. 1943 (January 27, 2021): id. 20202419, doi:10.1098/rspb.2020.2419.
2. Bosker and Peeters, "Beat Gestures Influence," p. 7.
3. Harry McGurk and John MacDonald, "Hearing Lips and Seeing Voices," Nature 264, no. 5588 (December 23, 1976): 746–48, doi:10.1038/264746a0.
4. Elana M. Zion Golumbic et al., "Mechanisms Underlying Selective Neuronal Tracking of Attended Speech at a 'Cocktail Party'," Neuron 77, no. 5 (March 6, 2013): 980–91, doi:10.1016/j.neuron.2012.12.037; Hans Rutger Bosker, Matthias J. Sjerps, and Eva Reinisch, "Spectral Contrast Effects Are Modulated by Selective Attention in 'Cocktail Party' Settings," Attention, Perception, and Psychophysics 82, no. 3 (June 2020): 1318–32, doi:10.3758/s13414-019-01824-2.