理解历法符号

this right here is a fresco by Raphael of Plato hanging out with his best student Aristotle and you may or may not know that these two fellows along with Plato's teacher Socrates are considered kind of the fathers of Western philosophy but that's not what this video is about I'm just this is actually just a small little video about different dates or maybe a better way to think about it different ways to specify dates or dating mechanisms and so if you were to look up if you were to look up Plato's birth well you might get either 428 or 427 but we'll go with 428 if you were to look up Plato's birth Plato's birth you might see it written as 428 BC or you might see it written as 428 b.c.e and the natural question is well what's the difference here they both have a BC but this one has an e it's the same year right now and the answer is is that these are referring to the exact same year in history but the acronyms here do stand for different things BC literally stands for before Christ before Christ so if the date is written 428 BC the implication is is that this is 428 years before the birth of Christ we'll see that we'll see in a second and that's not exactly right but that's what the implication is if someone writes BCE they're saying something very different the B still stands for before so the B still stands for before but the C II the C and C E does not stand for Christ anymore it now stands for common and so the C II part the C II part is common era common common era even though it's not referring to Christ anymore and this kind of this kind of the intention here so that it's it's I guess less religious than the term before Christ it's still kind of putting an importance on Christ's birth because it's saying that the Common Era is the time period after the birth of Christ which we'll see in a second isn't exactly right but so but there's actually the same exact dating scheme one with a with not directly referring to Christ one that is directly referring to Christ similarly similarly this right here is a painting of Christopher Columbus and if you were to look up in history book so you know when was his first voyage and did he show up in the and when did he first show up in the new world finding an island in the Bahamas you would see it written as either 1492 or ad 1492 or 1492 c c/e and once again these are all referring to the same year just using different accurate acronyms one of them's a little bit more religious or more directly refers to Christ and one is a little less religious so ad some people think it refers to after death it does not refer to after death because if you think about it if you have years before the birth of Christ and if you started if you started numbering after his death what would you know how would you number the years during his life so ad does not stand for after death it stands for Anno anno domini Domini which literally means a no means year and Domini means Lord or the Lord so it's the year of the Lord or the year of our Lord so it's years since and and1 anno domini would be the year of jesus christ's birth so not after death it stands for Anno Domini but literally year of our Lord so year since that Jesus was born with year one being the the implicitly starting with his birth and we'll see in a second that's not exactly right see e stands for Common Era Common Era once again once e e is the same thing as AD one sometimes we now write instead of writing ad 1492 we will write 1492 ad all referring to the exact same thing now all of these things refer to all of the you know when we say 428 BC it implies 428 years before the birth of Christ 1492 80 that's in the year of our Lord 1492 it implies 1492 years since the birth of Christ but the reality is is that we're not really quite sure when Christ was born and so these aren't exactly so if we you know Columbus didn't sail didn't sail across the Atlantic exactly 1492 years after the birth of Christ most historians put the birth of Christ at 7 to 2 BC or BCE depending on how you want to view it remember BC is before Christ which is a little ironic because we're talking about the actual birth of Christ BCE is before the Common Era and they put his death at 32 36 ad which is 32 36 in the year of our Lord or that's what this stands for Anno Domini or in the Common Era cee now some people they obviously don't like BC they don't like the BC ad naming mechanism because it's explicitly referring to Christ and every year it makes Christ a central figure in all of history so they'll say that this is clearly to Christian to Christian and they would they would prefer the situation they would prefer the less Christian naming scheme where you use BCE and and C II but a lot of people would still say hey look okay you changed well you know first of all some Christians wouldn't like this that you removed the direct references to the birth of Christ or being in the year the years since Christ's birth but even here and they'll say hey this you know you've removed it but even here some people would complain that although you've made the direct reference that this is saying comment before the Common Era and the Common Era even though you've removed the direct reference it still makes Christ birth the central thing in all of history but this is the convention whether you know people like it or a lot we've kind of in order to to have the same reference point and it to logistical e difficult to switch it this time everyone has essentially settled on this and it's really just a matter of letters of which which naming scheme you pick but the whole point of this video is that you don't get confused between BC and BCE you don't think that ad stands for after death it stands for Anno Domini in the year of the Lord or the year of our Lord and si e stands for Common Era but this and this are referring to essentially the same count after Christ after the birth of Christ or this theoretical birth of Christ which we don't really know when it actually happened it probably did not happen in what on at the beginning of 1 ad or 1 C II and these two things these two things both also refer to the same direction in the timeline one last thing I want to point out is is that there is no year 0 so if you kind of take these if you if you take either of these naming schemes you have so let's go very close to the year was one so there's just some point this theoretical birth of Christ which was probably not the actual birth of Christ but at that theoretical point right at that so New Year's so you have kind of a you know December 31st of the previous year all of a sudden now you are on January 1st of 1 a d ad or c e depending on how you want to refer to it and the year before that the year before that was was one was one BC 1 BC or BCE depending on how you want to refer to it so there is no year 0 in this scheme and then the last thing I want to emphasize and it might be obvious to you is the larger a number you have here the further back you're going in time because this is saying how many years before this theoretical birth of Christ and obviously larger numbers here you have here this is the further you're going off into the future and if you wanted to figure out how many years passed between Plato's birth and Columbus sailing across the Atlantic to to to find the new world you would say well look it took 428 years to go from Plato's birth to this theoretical birth of Christ and then it's that you have another 1492 years to wait until Columbus gets his ship together so the total number of years would be I'll do it right over here 428 years to get to Christ from Plato's birth and then you have another fourteen hundred and ninety-two years to wait for Columbus so let's the eight plus two that is ten as you could see I just wanted to add a little arithmetic in this video so one plus two plus nine is 12 and then we have nine 1 plus 4 plus 4 so 1920 years between Plato's birth and and Columbus sailing across the Atlantic