A polymath is defined as a person with a wide knowledge of many subjects, and whilst the physics community has thrown up many such individuals over the centuries, few have demonstrated such proficiency across multiple disciplines as Thomas Young - a person who has been described as “the last man to know everything”! That might seem like a pretty big boast on his behalf, but when you stop to think about the breadth of his achievements, the justification of that hyperbole seems remarkably close to the truth.

Thomas Young was born in 1773, in Somerset, England, into a family of Quakers; it didn't take long for his prodigious talents to become apparent. As a teenager, he was already proficient in a dozen or so, mostly antiquated, languages. Largely self-taught as a youth, he went on to study medicine in London, Germany and Edinburgh, eventually ending up at Emmanuel College, Cambridge (Emma's alma mater). Already a fellow of the Royal Society at the tender age of twenty-one, lectured in physics at the Royal Institution, an organisation riding on the crest of a wave of discovery with eminent directors like Humphry Davy and Michael Faraday. In 1811, Young took up a lifelong post as physician at London’s St. George's Hospital. It might be argued that his dedication to the medical world makes his achievements as a physicist all the more remarkable given the time constraints notoriously imposed by that profession.

Sadly, Thomas Young only reached the age of fifty-six, but he managed to pack into that modest lifespan a wealth of achievements that most ordinary mortals could barely aspire to dream of. The list of his accomplishments is astonishing. He is, perhaps, most famous for his “double slit” experiment, the results of which, building on the work of Christiaan Huygens, demonstrated once and for all the wavelike nature of light, whilst flying in the face of the then universally trusted corpuscular theory of light espoused by the likes of Isaac Newton. He showed how different colours corresponded to different wavelengths of light, work which tied in with his studies of the human eye, leading him to an understanding of how the eye focuses, the causes of astigmatism, and the existence of the different colour receptors. To begin with, his wave theory of light was poorly received in Britain, however, it was soon to be vindicated by the discoveries of Augustin-Jean Fresnel, in France where Young's work was hitherto unknown.

Now, in a world before the internet and telecommunications in general, it's not surprising that occasionally someone gained credit for principles that had already been understood or put into practice, so we can't judge too harshly the fact that another of Young's most famous achievements wasn't entirely original: namely Young's modulus, the relationship between the tensile stress and strain of a material, which extended Hooke's Law (pun not intended!), and had been utilised decades previously by Euler and latterly Riccati - the reverse scenario, one might say, of the situation regarding Fresnel and Young!

Perhaps less well-known is Young's work on surface tension and molecular forces, where he brilliantly estimated the size of water molecules, based on the assumption that the range of attraction between them was in the same order as their size.

Young was a leading proponent in our understanding of the nature of energy. He did pioneering work in the understanding of the dynamics of blood flow. He contributed articles on languages to the Encyclopedia Britannica, having analysed literally hundreds of languages and he famously, in conjunction with Jean-François Champollion, contributed to the understanding of ancient Egyptian hieroglyphics. He even developed a new way of tuning musical instruments according to the prevalence of certain musical keys!

In short, Thomas Young’s historical contribution to our understanding of science, medicine and language was by modern standards extremely wide-ranging. It's not clear that someone could come along now and do the same. He had the advantage of independent wealth and, especially in his youth, the time to indulge his many passions. He was also an extremely talented individual. Will we ever see the likes of him again? Probably not, since the sum of human knowledge required, in order to make significant scientific progress in any one field, let alone many, has exploded “astronomically” in the intervening period. However, maybe there is a reminder here, for the scientific community to act as a whole, in realising the importance of interdisciplinary research to unlock the secrets of its constituent parts.

Images:

Thomas Young by Henry Perronet Briggs - http://rstb.royalsocietypublishing.org/content/370/1666/20140308, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=109315084

Areas of Knowledge by IB (2022+). Theory of Knowledge aubject brief - https://www.ibo.org/programmes/diploma-programme/curriculum/dp-core/theory-of-knowledge/