so now it's time to close Unit 8 and consider the cultural and intellectual developments that occurred throughout the 20th century and baby they were profound so if you're ready to get their brain cows milked let's get to that when the 20th century began there was a widespread belief in the inevitability of progress which was brought forward from the 19th century starting with the Scientific Revolution and into the enlightenment science had solved so many of our Collective problems as human beings and so at the turn of the century we were basically on the precipice of a utopian civilization the 20th century is going to be great y'all but then Europe went ahead and plunged itself into World War one and all that sweet smelling optimism disappeared like a fart in the wind now to be fair this shattering of belief in progress had started before World War one but it was mainly confined to artists and a handful of elite folks but once the War Began people could see what all this progress in science and culture gave us scientific breakthroughs and chemistry gave us chlorine gas and mustard gas which choked and killed hundreds of thousands on the battlefield breakthroughs in mechanical engineering gave us the machine gun which mercilessly mowed down millions of Europe's young men scientific breakthroughs that occurred in medicine with the widespread use of vaccines and sanitation but those were just used to send men to the Slaughter and then care for them in their wrecked state so the point is after World War one had ended that disillusionment about the notion that Humanity was progressing were almost perfect filtered down from the elite circles and spread more generally to everyone else now it wasn't only two World Wars that had people questioning their beliefs about reality scientists made new discoveries during this time and helped people realize that their grasp on reality was not as firm as they thought now remember what a triumphant moment it was when 300 years prior Isaac Newton had published his laws of physics and all of a sudden we knew how the world worked nature was governed by immutable laws that could never be changed and then remember how great it was in the early 19th century when chemist John Dalton had articulated his theory of Adam how there were these hard bits of matter that constituted the basic building blocks of all that exists so we finally figured out how everything works and now we can focus on other problems but in the early and mid 20th century a group of new scientists came along and shattered all those Illusions first was Albert Einstein whose work helped us to see that time and space are not fixed realities at all instead in his theory of relativity Einstein discovered that time and space are actually relative to the observer in other words the faster a person moves through space Einstein argued the slower time would move and then came Verner Heisenberg who built on the work of previous physicists who had discovered that the atom was not in fact the smallest unit of reality they discovered subatomic particles like electron but still everyone believed that electrons behaved predictably but Eisenberg was like oh that's so cute what he discovered is that the act of observing an electron with light which is you know how you observe an electron changes the behavior of the electron so in that way we have no stinking idea how subatomic particles move because they change based on how we observed then came the work of Enrico Fermi and Niels Bohr both of whom were able to harness the explosive power of splitting atoms and that Discovery led to the development of the atomic bomb which killed hundreds of thousands of Japanese people at the end of World War II and created a right mess in international relations during the Cold War and then there was a developing science of people's interior world with the rise of psychology are we human beings like to think that we act according to our rational nature and that we commonly reason out what to do next when presented with stimuli from the world nothing came along Sigmund Freud who argued that under the surface human beings are completely irrational instead of making decisions based on reasoned analysis Freud argued that we actually behave mostly on unknown impulses deep within our site so whether it was our understanding of how the world worked or how human beings themselves worked the emerging science of the 20th century was undermining all our beliefs about a certain and predictable Universe also thanks to World War One a whole generation of those who came of age during the war were saddled with disillusionment in Malay it was writer Gertrude Stein who called them The Lost Generation all of a sudden they felt a drift in a post-war culture values and mores that they had inherited from their parents no longer seem to work in the world that the war had created you can see this especially in the writings of Ernest Hemingway and F Scott Fitzgerald additionally women experienced a profound change in the 20th century hundreds of thousands of women joined the military to serve in auxiliary positions like nurses and office workers in addition because the men had to go off and fight the war they took up domestic jobs as well many of them in factories during both world wars this newfound Liberty outside of the home led to a rise in the efforts of women to gain the right to vote and though it would take another 30 years after the close of World War II for All European women to gain the franchise and Democratic countries slowly but surely it did occur okay that's the end of Unit 8 and click here if you're studying for an exam it's my AP Euro review pack which will help you get an A in your class and a five on your exam inmate if you want to keep reviewing for Unit 8 then click here in this playlist will make all your dreams come true I'll catch on the flip-flop I'm Laurent