[Music] Thomas Kuhns the structure of scientific revolutions published in 1962 was itself a revolutionary approach to the philosophy of science the book was both influential and controversial born in 1922 Combe began his career as a physicist before turning to the history of science he was interested in how scientists approach their daily work and in thinking about the question of how science develops over time Kuhn saw science is progressing in two alternating phases one called normal and the other he called extraordinary or revolutionary scientific development is traditionally thought of as simply moving faster when a discovery is made like the discovery of bacteria or the realization that the Earth revolves around the Sun and not the other way around but for Kuhn the normal and extraordinary phases of science aren't just different speeds of discovery but fundamentally different approaches to scientific work let's look at the normal phase of scientific work the traditional view of science looks something like this there are text books describing observations laws and theories that a talk to students in schools the science within this body of knowledge is simply a constellation of facts theories and methods that are contained in those textbooks and in the way they're taught great scientists are those that have contributed to that body of knowledge this stockpile of scientific knowledge grows over time science then according to this view is cumulative discoveries are added to the pile sometimes at quicker speeds than others normal science the day to day scientific activity is based on this stockpile this body of knowledge Kuhn calls this a paradigm a paradigm has approaches laws theories ways of applying instruments machines a network of assumptions of facts that all work together a model or a pattern the paradigm Kuhn writes provides a map whose details are elucidated by mature scientific research and since nature is too complex and very to be explored at random that map is as essential as observation and experiment to Sciences continuing development through the theories they embody paradigms proved to be constitutive of the research activity Kuhn also sometimes calls this map a disciplinary matrix the map disciplinary matrix or paradigm contains a particular selection of facts like positions in astronomy the mass of materials wavelengths boiling points acidity levels all that have shown to be particularly revealing of the nature of things Kuhn writes there are also a class of instruments and machines that can measure these things and explore them further plus engineers that seek to improve these machines and instruments based on acquiring more sophisticated readings of the possible facts finally there are problems lacks in the map gaps in the knowledge areas where theories need expanding or confirming I have met the heaven chartered the causes of the planets with this money I will build a real telescope it should be as long as a cannon as big around as a wine cask it will weigh more than the COO refers to this normal science simply as puzzle solving the puzzles are assumed to have a solution based on this collection of theories fact scientists and instruments there are assumptions that direct the puzzle solving most importantly that this selection of pieces will solve the puzzle but sometimes they don't sometimes the pieces don't fit and sometimes the rules of the puzzle need to be abandoned firming the kun rights for example that throughout the 18th century those scientists who tried to derive the observed motion of the moon from Newton's laws of motion and gravitation consistently failed to do so as a result some of them suggested replacing the inverse square law with a law that deviated from it at small distances to do that however would have been to change the paradigm to define a new puzzle and not to solve the old one in the event scientists preserve the rules until in 1750 one of them discovered how they could successfully be applied only a change in the rules of the game could have provided an alternative an anomaly occurs when a piece of the puzzle just went fit this can lead to a crisis in the paradigm and search for a new one increasingly problematic anomalies and a consensus that there is an anomaly leads to increase the bait different perspectives on what could change disagreements and a new type of experimenting yukine writes that when for these reasons or other like them an anomaly comes to see more than just another puzzle of normal science the transition to crisis and to extraordinary science has begun the anomaly itself now comes to be more generally recognized as such by the profession more and more attention is devoted to it by more and more of the fields most eminent men this leads to the pursuit of extraordinary science which might lead to a revolution this extraordinary phase is consist of a loosening of the rules of research more experimentation and creativity more randomness trying new and unique experiments and a deconstruction of stereotypes the reading of different philosophies he writes that the proliferation of competing articulations the willingness to try anything the expression of explicit discontent the recourse to philosophy and to debate over fundamentals all these are symptoms of a transition from normal to extraordinary research this if successful can lead to a complete change in perspective a paradigm shift where a completely new perspective like Newton's laws of physics or Einstein's relativity or quantum mechanics can appear he sometimes described the state of affairs that leads to this pre paradigm attic because it's like the Wild West there's a lack of consensus the trying of anything a storm of experimentation and competition between different schools of thoughts a shift in paradigm is like the shift in perception from the rabbit to the duck in the gestalt image nothing has changed apart from your psychological perspective two people with the same sensory impressions concede two different things Ptolemy saw the Sun revolving around the earth nothing had changed though when Copernicus described it as being the other way round just a change in perspective under a certain paradigm scientists look in a particular eyes duay with a limited constellation of assumptions and ideas at for example the equipment in the lab the materials around them are their colleagues in the conversations they have or might possibly have with them okay so let's take an example the discovery of oxygen in the 18th century was a revolution in chemistry before this the dominant views of paradigm inherited from the Greeks was that there were four distinct elements only earth water fire and a the leading theory that grew from this was that combustible materials contain something called suggestin that enabled them to burn when they burnt they released their logistic but when ore is heated and turned to metal it gains weight for the most part this anomaly was ignored or explained as phlogiston from the coal transferring into the metal when metal rusted you could see the phlogiston leaving it they said but this led to another problem rusted metal gains weight it weighs more than normal metal and again this was largely ignored because it couldn't be solved with the pieces of the puzzle supplied by the reigning phlogiston paradigm slowly two things combine to create a crisis the increase in the precision and importance of using weights and the invention of pneumatic chemistry that used equipment like air pumps to compress air and see the effects of gases these air pumps meant you could burn something and see air being released it meant that the phlogiston theory was put under increasing strain there was more and more that it couldn't answer then two chemists the English Joseph Priestley in the French Antoine Lavoisier conducted innovative experiments that focused on burning different materials and weighing the results they performed experiments not too dissimilar to this but with more sophisticated equipment burning materials in a vacuum and recording weighing the results the point for is that in a vastly complicated world what you're concentrating on and the tools and instruments you use makes a huge difference to the results Priestley discovered the heated mercury calx produces air when burnt and that if you burn a candle in this air it burns even brighter than normal air what's special about mercury calx is that it burns with that coal without fuel with just a flame or a light from a magnifying glass yet it produced something without phlogiston Lavoisier's saw that while some metals increased their weight when burned because of what we now see is oxygenation others lost weight he realized it wasn't phlogiston but the air entering into and leaving the metal he named this air oxygen a Vasya discovered in 1777 the oxygen theory of combustion a paradigm shift that changed the rules of chemistry now rather than chemists focusing on the phlogiston theory they focused on the oxygen theory and the possibility that rather than four elements the world was made up of many more chemicals we can see something similar going on in the Copernican Revolution in the 16th century Ptolemy system that the earth was at the center of the universe was pretty good it predicted the position of the stars and can actually still be used today but it often failed it couldn't quite predict the position of the planets or equinoxes over the centuries stargazers knew that something was wrong when Copernicus realized that the earth went around the Sun it started a paradigm shift that altered a huge range of scientific assumptions Newton did the same for gravity Aristotle had thought and this was the reigning paradigm that objects moved towards the ground because it was in their nature Newton saw that all bodies attracted others discovering the general laws of physics the qu notes how paradigm shifts are usually sparked by young creative or eccentric individuals or scientists new to the field people not embedded so deeply in the assumed paradigm they see things in completely new ways paradigms change how we perceive the world what we see when we look at the Stars or when we burn a piece of wood and every historical society assumes their worldview is the correct one but if history tells us anything it's that those assumptions are often wrong and this might be the very telescope of which Galileo dreams indeed it is a direct descendant of the tiny spyglass he invented and with which in 1610 he discovered four satellites of Jupiter almost three centuries elapsed before scientists using this 36 inch refracting telescope at the Lick Observatory of the University of California discovered a fifth satellite since then for more a beam discovered three of them with this telescope if you like these videos I need your help and here's my request if you think you get the same value from four of these videos as you do from just one cup of coffee then please consider pledging just $1 per video that's three to four dollars per month to keep this channel going you can even limit your pledge to one dollar a month and if you pledge $5 out add your name to the credits to those that already support them and I thank you so much this channel just wouldn't exist without you you can also hit like share follow me on Twitter and Facebook etc all of these things really contribute to helping Ben and I grow thanks for watching and see you next week