Duke professor probes 'why time flies and beauty never dies'

It's a happy revelation to learn how physics explains our everyday perceptions of time and beauty, thanks to the work of Duke University professor Adrian Bejan, who presents the physics involved in understandable terms.

Bejan's most recent book, "Time and Beauty: Why Time Flies and Beauty Never Dies," indeed answers both questions in the title and provides essential guidelines for design and engineering students as well as lay readers.

Bejan explains the physics of perception and how visual images convey our perceived changes in stimuli, the way the sensory images reach the brain, and how the speed of these images, compared to clock time, changes as we age.

Many people know the feeling that time flies, so it may be satisfying to learn that there is a physical basis for this perception.

As Bejan points out in "Time and Beauty," the new physics can empower people to a higher level.

A book sparked by curiosity

Bejan said curiosity led him to write "Time and Beauty."  

"During school and basketball training in the 1960s, I noticed that the hours [and the games] were getting shorter," he said. "I remained curious about my perception that ‘time flies.' Along the way, I found that many people share this feeling. 

"One day, I don’t know why--for fun, I guess, I discovered the physics of why the ‘time flies’ perception is common," he said. 

He wrote an article exploring the idea that was published in Cambridge University's journal European Review.

"My journal article was published in March 2019," Bejan said. "Weeks later I was surprised by an e-mail from a platform that keeps track of most-read articles. The email said that my article was (by far) the most read during the month of March."

This popularity gave him the idea of pursuing a book, by highlighting "the fact that everybody is getting old and worrying about the diminishing supply of time," he said. ''‘Everybody means the widest audience imaginable. For this audience, a serious book is more useful than one physics article in a journal."

From saccades to design principles

Bejan had already pursued the physics of beauty perception in an earlier journal article, and he said,  it was "fortuitous for my book project that the physics of time perception is the same as the physics of beauty perception," the subject of his 2009 journal article. 

"The common physics resides in the ‘scanning’ movement performed by the two eyes," Bejan added. "The scanning is done by violent and very frequent jolts, called saccades. Scanning is the cause of two perceptions, the change in the image, and the shape of the same image."

Bejan teaches engineering students at Duke University, where he is the J.A. Jones Distinguished Professor. His exploration of time and beauty has definite implications for future designers.

The constructal law

"Like all the other features of human design (locomotion, organization, language) perceptions such as time and beauty are manifestations of the universal tendency of design evolution in nature, the constructal law," Bejan said.

The constructal law, proposed by Bejan in 1996, states that for a finite flow system to persist in time, it evolves with freedom such that it provides greater access to what flows. This includes all systems such as blood flows, river flows, human migration. 

"The constructal law," Bejan said, "is a concise statement of universal observations, both biological and non-biological, that for a flow [moving] system to persist in time it must evolve with freedom to configurations that provide easier and greater access to what flows."

Concerning time and beauty, Bejan added, "From physics time perception means observed changes in the image, and beauty perception means the observed shape. To perceive both faster is essential for human life; longer life, safer, faster movement, more economical, more innovative. It is useful to get out of the way of danger faster, and to be attracted to useful things, like easier to understand images, faster."

A `crystal ball'

"Knowing the physics law of evolution is like owning a crystal ball," Bejan said. "Students and future scientists are the chief beneficiaries of owning it. Using physics, one can predict and identify the best designs. It is important to know the physics law of evolution because with the law we can predict what will happen naturally."

"In addition, if we are inventing artifacts that empower us, we can fast-forward their tape of technology evolution to designs that are close to the best, even though they will never be the best," he added. "The ‘best’ does not exist, because evolution never ends."

The main takeaway from his book, Bejan said, is that "the discovery of the physics behind the perceptions of time and beauty is a significant step in fundamental physics because it places the ‘intangibles’ (human perceptions) in physics. Science is about us, from us, for us. Science does not grow on trees in the summer."

He also emphasized, "In addition to time and beauty, the book unveils the physics of other perceptions such as contrast, perspective, prospective, learning, usefulness, memory, dreams and art. The book teaches pictorially the science of form, configuration, design and evolution."

Useful lessons

Students are not the only beneficiaries of learning the physics of time and beauty. Bejan said this kind of study offers lessons for all.

"[Take] time," he said. "If the aging person wishes to slow down the ‘mind time,’ one way is to work tirelessly to get away from the routine. It is to introduce changes, more changes, that impress the eyes and the mind with their frequency and novelty, as in infancy when the eyes were scanning the world at high frequency because everything was new.

"Creative persons do not need such advice, because they constantly contemplate new mental images (ideas)," he added. "The rest of us may use this lesson if we wish." 

The opposite is true, however, for someone in prison as Bejan noted, "Stick to a routine that accelerates your mind time and shortens your perceived time to freedom."

Bejan has similar advice for understanding beauty.

"It is useful, which is why we are attracted to it," he said. "The record of the attractiveness goes back to antiquity (e.g., Venus de Milo). During the Renaissance, beauty acquired the ‘golden ratio’ label in architecture, painting and design. The golden ratio is the shape of the image that is scanned the fastest, because it most efficiently fills the visual field, and it was predicted by invoking the constructal law."

"The more beautiful image is remembered longer," Bejan said. "Beauty ‘never dies’ because its life is far longer than one human life. The mind time ‘flies’ because one human life is finite."

The takeaway

"The physical basis of time and beauty is the physics of human cognition," Bejan concluded. "As the great illusionist Harry Houdini put it, `What the eyes see and the ears hear, the mind believes.'”

Bejan received the Benjamin Franklin Medal in 2018, and has received 18 honorary doctorates from universities in 11 countries. He has published widely on thermodynamics, evolution, and the constructal law of organization in nature, as physics.

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Adrian Bejan, "Time and Beauty: Why Time Flies and Beauty Never Dies." (New Jersey: World Scientific) 2022. 

ISBN 9789811246791