While I consider Young to be a citizen scientist as worthy of the title as anyone else, the next best word to describe him is "Polymath" - a person with a wide-ranging knowledge of many subjects. He was a medical doctor by training but made important discoveries in a wide number of fields, including optics, mechanical stress, tidal fluctuations, Egyptology and languages. So even though he had academic training in the sciences he is still a citizen scientist to me...a person without formal training in these other fields who made important advances by independent reading, study and testing. He is also a model for many modern-day researchers who may be accomplished in their field and beginning to retire, but still looking to contribute or transfer their knowledge to a brand new field. Young did it in his day, and while some things have changed, there is still room in the world for polymaths like him.
Modern-day author Andrew Robinson has noted that history can be particularly unkind to polymaths like Young. Would-be biographers may be nervous about tackling a subject whose range of skills far exceeds their own. The general public also has trouble remembering them due to their wide-ranging activities...there is no mental 'slot' available to easily remember them.. So polymaths are forgotten or, at best, squashed into a category we can recognize. But Robinson himself has attempted to buck that trend, tackling Young's life and accomplishments, and explaining the science of numerous fields, in the biography "The Last Man Who Knew Everything".
One of the best markers of Young's diverse interests is in the numbers of articles he wrote, or co-wrote for the Encyclopedia Britannica. Unlike the modern Wikipedia where anyone can write while the community edits, one needed to be an authoritative source to assist with the Britannica. The list of topics Robinson describes him writing about authoritatively include: alphabet, annuities, bathing, bridges, capillary action, carpentry, cohesion, color, dew, double refraction, Egypt, eye, focus, friction, halo, Herculaneum, hieroglyphics, hydraulics, languages, life preservers, motion, resistance, road-making, ships, sound, steam engines, strength, tides, waves, and weights and measures. And that's just part of his bibliography.
Of all Young's writings for the Encyclopedia Britannica, the article on 'Egypt' is the most cited contribution today. In the late 1700's French troops under Napoleon discovered an intriguing tablet in Egypt containing passages from three distinct languages: Ancient Greek, Demotic (an Egyptian language), and Hieroglyphics. Since Greek was still well known hopes were immediately raised that this "Rosetta Stone" would finally let scholars crack the code of two unknown languages, Demotic and Hieroglyphic. In true citizen science fashion French officials chose to make everything public and "crowd sourced" decipherment as copies of the Rosetta Stone were made and distributed to the scholars of Europe during 1800. Even back then the concept of open science was alive and well.
Unfortunately the world would wait another 14 years for a number of crucial insights to be made. As Robinson describes in the book:
It was his powerful visual analysis of the hieroglyphic and demotic inscriptions on the Rosetta Stone that gave Young the inkling of a crucial discovery. He noted a 'striking resemblance', not spotted by any previous scholar, between some demotic signs and what he called 'the corresponding hieroglyphics' - the first intimation that demotic script might relate directly to hieroglyphic, and not be a completely different script, somewhat as a modern cursive handwritten script partly resembles its printed equivalent.Young did not have any of these insights from a long academic study of Egypt or ancient languages. Instead it was his penmanship. He had co-authored a book on the subject and became intimately familiar with how the act of drawing letters and how drawing can change over time. This let him see commonalities between the languages all other researchers had missed. He had also time in his thirties preserving and copying ancient papyri discovered in the ruins of Herculaneum (an ancient Roman town catastrophically destroyed by a volcano) providing much practice in the actual handwriting practices of ancient Romans and Greeks.
From 1814 until his ultimate death in 1829 Young made a number of important discoveries, including identification of hieroglyphic plural markers, various numerical notations, and a special sign used to mark feminine names. But his most important discovery, following his two insights in the demotic-hieroglyphic relationship, was with cartouches (short character sets enclosed in an oval). While previous researchers had come up with the idea that cartouches expressed royal or religious names and that foreign names in the cartouches might be spelled phonetically, Young was the first to identify three of the six cartouches as referring to Ptolemy and used that information to identify those letters throughout the Stone. Once those were in place he could move through and eventually cracked the large majority of demotic script. Others (such as Jean-Francois Champollion) could also build on the discoveries and decipher the rest of the hieroglyphic (non-demotic) characters.
Impressive as this is, Egyptology was not even his first love.
Young was born in Milverton, England in 1773 and became a medical doctor at the age of 23. While moderately successful as a doctor an inheritance from a rich uncle allowed Young to continues with medicine while pursuing many other intellectual pursuits. Over the years he would join the Royal Society, become a salaried "inspector of calculations" and physician for the Palladium Life Insurance Company, advise the Admiralty on methods of shipbuilding, preside as secretary of the Board of Longitude, and become superintendent of the Nautical Almanac.
One of the strong influences in his voracious curiosity and experimental nature was his Quaker upbringing. In fact there was a disproportionately large number of Quaker physicians and scientists in eighteenth - and early nineteenth-century Britain. One reason was probably that "despite the emphasis on discipline", each member of the Society of Friends was "encouraged to form his or her own views on any subject" as noted by the historians John Brooke and Geoffrey Cantor in their survey of Quaker (and ex-Quaker) fellows of the Royal Society.
Throughout his life, Young was keen on the idea that what one man had done, another man could also do; he had only a small belief in individual genius.Young also liked to use his hands and make experiments in the time-honored Royal Society tradition, But he liked even more to use his mind, by reading all the authorities on a subject and coming to his own conclusion, which might lead him to an experiment of his own. In fact most of his time at Cambridge would be spent in solitary reading, writing, and doing experiments in physics in his dorm rooms.
"His pursuits, diversified as they were, had all originated in the first instance from the study of physic: the eye and the ear led him to the considerations of sound and light."One of his early discoveries was in the human eye. While optometers had been previously developed to measure vision, Young further developed the device and discovered his own astigmatism, a condition not named for another three decades by William Whewell. He then went further and used it to better understand how the eye focuses. This had been a controversial subject for years with many different hypotheses proposed but not proved. It was Young who used his optometer to test various eye focusing hypotheses on himself. Eventually he ruled out various potential answers (such as the curvature of the cornea or the length of the eyeball changing) and found that focusing occurs when the shape of the eye lens changes.
Another major contribution to understanding the eye came in a lecture to the Royal Society. While Newton introduced the term 'primary colors' (proposing seven and now reduced to three), there was no understanding of how these colors created hues distinguishable by the eye. Young proposed that brain would receive red light, with the longest wavelength, as red because it would stimulate only one type of receptor. Same thing for yellow with a shorter wavelength and blue for the shortest. Light of intermediate wavelengths would stimulate multiple receptors in proportionate amounts. Young was first to propose it yet it took until 1959 before scientists made the definitive experiments that finally proved Young's idea that color must depend on a retinal mosaic of three kinds of detectors.
By improving upon Newton's ideas Young reinforced the standard scientific concept that even established concepts must always be challenged and revised as new facts and knowledge come to light. It works for the sciences and its key to the citizen science concept that everyday people should not be afraid to thoughtfully challenge existing dogma. As Young himself said, "...as much as I venerate the name of Newton, I am not therefore obliged to believe that he was infallible. I see, not with exultation, but with regret, that he was liable to err, and this his authority has, perhaps, sometimes even retarded the progress of science."
Young is also known for demonstrating his general law of the interference of light. With light, he realized, constructive and destructive interference would produce patterns of alternating bright and dark, rather than areas of agitated and smooth water. However, the position of these patterns would be different for different colors, because, as he hypothesized, color depended on wavelength. Young also performed experiments measuring the wavelength of red light at 0.0000256 inches, close to it's currently-known value.
Much of this culminates (from a scientific history standpoint) in his first describing the famed double-slit experiment. A vital contribution to modern quantum mechanics, historians still don't know if he actually performed the experiment. But at least his thought experiment showed the wave characteristics of light and demonstrated that it is not a particle, as Newton and others had previously thought.
But there is still more.
In the field of traditional physics, Young grasped the importance of what physicists would later term the kinetic energy of a moving body, and was the first to describe energy in its modern scientific sense - as a measure of a system's ability to 'do work'. He also created theories of tides that differentiated between force vibrations (gravitation of moon) and those from oscillation of water. By treating both as interacting pendulums he could successfully predict tides in canals and narrow seas, something which had not been done before.
Robinson sums up many of Young's other accomplishments this way:
But it is not only the physicists who can claim Young as one of their own. He has on honored place in engineering, physiology, and philology, too. Open any engineering textbook and you cannot fail to encounter "Young's modulus", a fundamental measure of elasticity derived from Hooke's law of stress and strain; Young's modulus is the ratio of stress acting on a substance to the strain produced...Far less important, though still noteworthy, are: "Young's rule" in medicine, a rule of thumb for deciding how to adjust an adult drug dosage for children' "Young's temperament" in music, a way of tuning keyboard instruments, such as harpsichords; and Young's principles of life insurance.Sadly Young died at the relatively early age of 55. Who knows what else he could have discovered given another five, ten, or twenty years of experimental work. But just in that short time he revolutionized numerous established fields and drew much acclaim, and derision from it. As Robinson states, "Academic disagreements came about because "It is a disturbing thought, especially for a specialist, that a non-specialist might enter an academic field, transform it, and then move onwards to work in an utterly different field." But that is essential to moving science forward and is the basis of citizen science. So in many ways I consider this yet one more of his powerful innovations.
Finally, I'd like to end with two quotes from Young's that neatly sums up much of what I feel about open science, the value of following scientific passions outside your ones area of training, and the ability of people to participate fully with trained, professional researchers:
Although I have readily fallen in with the idea of assisting you in your learning, yet [there] is in reality very little that a person who is seriously and industriously disposed to improve may not obtain from books with more advantage than from a living instructor...Masters and mistresses are very necessary to compensate for want of inclination and exertion, but whoever would arrive at excellence must be self-taught.And:
It is well for me that have not to live over again; I doubt if I should make so good a use of my time as mere accident has compelled me to do. Many things I could certainly mend, and spare myself both time and trouble; but on the whole, I had done very differently from what I have, I dare say I should have repented more than I now do anything -- and this is a tolerable retrospect of 40 years of one's own life...I have learned more or less perfectly a tolerable variety of things in this world: but here are two things that I have never yet learned, and I suppose I never shall -- to get up and go to bed. It is past 12, and literally Monday morning as I have dated my letter, but I must write an hour longer.