so how did we get here as i said it wasn't it isn't one particular thing it's a it's a number of different um events contexts that help to make possible the study of the mind so these small contributions from a variety of different contexts that we're going to have a look at next i'm actually going to start with the ancient philosophers plato and aristotle because these two were really the first um to in any sort of serious or documented way discuss thinking about thinking you know the literally recognizing that people have thoughts and how do thoughts work and where does knowledge even come from so plato was the older he was the mentor of aristotle who is the younger and even though plato was the mentor plato was more of a speculator his philosophy was really pretty abstract and a bit on the mystical side he didn't actually also check his beliefs with the world around him so for example he believed that ideas and principles were innate placed in the minds of human beings by a superior being this form of thinking is called nativism the idea that we are born with innate knowledge so aristotle as i said was plato's student and he actually took the opposite perspective he believed that knowledge was gained through experience this form of thinking is called empiricism because it relies on empirical observations now we're gonna jump ahead uh by you know ah not quite two thousand years but like a long time to rene descartes and there's a very specific reason for that while there is a long period a long gap here um during that period it was it was basically the dark ages there was a lot of war famine um literally just basic survival was more on people's minds than um than thinking about thinking and so um while there were a few treaties and essays here and there throughout this historical period we don't start to see a real interest again in the mind until the renaissance essentially so around the time when the um when the royal society was founded and so this brings us to descartes descartes perspective so i resolved that everything that ever entered into my mind was no more true than the illusions of my dreams but i soon noticed that while i thus wished everything false it was necessarily true that i who thought so was something that's actually a really brilliant observation um descartes perspective so descartes was also a nativist interestingly uh similar to plato and so he really thought that ideas were innate descartes perspective came from the fact that he figured this out without any observation he actually just was sitting um probably by the fire cozy and just thinking about things and coming to realizations he conceded that people did acquire knowledge through experience but he said that innate ideas were more important and really compromised a set of universal truths and that these ideas arise from consciousness not from the objective world external objects might be able to remind you of those ideas but the ideas themselves come to us um don't come to us through the sensations they they come to us through uh innate knowledge newton isaac newton i'm i'm going to um i'm going to highlight here because even though he did not really speak about um the mind or psychology he was a major figure in science and so he was a member of the royal society and keep in mind that he existed at a time when the scientific method was just being described so there was a state of manic bliss among natural philosophers once they figured out the scientific method because every question in a sense was a question worth asking and so um isaac newton is attributed with describing a lot of basic universal truths around science because um and in a variety of different fields because he was alive he was a genius but he was also alive when we figured out the scientific method it was you know imagine like people groping around in the dark and suddenly somebody turns on a light like yeah man everything is interesting so you've got this genius who now has the tools to actually answer very specific questions so isaac newton was actually making a lot of scientific discoveries and including the idea that white light is actually composed of um the entire all of the colors of the visible spectrum and this illustration here this painting is actually um i i love it and it's illustrating a very specific story from um from isaac newton's life so uh the plague broke out when he was a student at cambridge and there was there was um there was a epidemic and they sent everybody home for a lockdown essentially and um isaac newton bored smart board uh just did a bunch of experiments and one of them to test this idea of whether or not light was broken down into its individual components um he waited he created like so he had this this window and some curtains some some blackout curtains over top and the the story is that he poked a hole through the curtains and then he had to wait all day for the sun to appear at that perfect location to shine light through the hole and then he passed that beam of light through one prism in order to show that you could break it apart into its constituent parts but then he passed it through another prism to show that you could use a prism to put all of those colors back together again in order to produce a white light so demonstrating that white light it can be broken up into its elementary components now the reason that i highlight this is because of who comes next and who comes next is a natural philosopher named john locke so john locke was um he was a hardcore empiricist he was inspired by natural philosophers and people like isaac newton and the idea that light could be broken up into its constituent parts um that was inspirational to him he was also really attracted to the idea of like chemical compounds being composed of elements that were called molecules like that was super interesting and so locke wanted to show that there was a similar concept at work in the mind that ideas and knowledge were composed of elements that could be broken down and when they got combined that was what what led to the experience of consciousness suggesting that complex ideas form smaller are formed from smaller molecules of ideas so for example a cherry the idea of a cherry is a combination of things like red and sweet and round and it's when they all come together that we have a conscious experience of a cherry and i love this image because it's left-handed uh hey everybody can i get like a hey from all my lefties um but it's actually meant to illustrate something else so john locke not only talked about this idea of this idea of elemental sensations he also gave us a very important idea of tabula rasa um blank slate so john locke was an empiricist he thought that these elemental sensations um and all of the complex concepts that they formed were all knowledge derived from experience period we are blank slates at birth ready to accept knowledge through experience so just like this blank uh slate here it's ready to accept the writing of this person but um it doesn't have anything on it to begin with so this idea what's interesting is that this idea was very attractive to political reformers at the time who were contesting their astra the aristocratic system of governments in which the king was born into powers and rights they were trying to establish a democracy essentially and they were trying to make the point that um kings and noblemen were not categorically distinct from the lower classes of england that um and that that was very attractive so next we're gonna add to the pot so this is this is another piece of the puzzle erasmus darwin erasmus darwin was charles darwin's grandfather and he was a real renaissance man he was the physician to king george iii um but he also published books on botany and poetry he was an inventor and he also advocated for women's education which you know he was he was very liberal in today's standards he was also a vocal proponent proponent of evolution the concept that species change over time during erasmus day the fact that species changed over time was still questioned so charles darwin didn't propose the idea of evolution this idea was already floating around in the ether um and uh a lot of people believed that the species on earth were crafted by god as they were so they were immutable they were unchanging they were perfect because god designed them um but then there was some evidence that in fact species change over time so for example there are structural similarities across species primates for example all have five digits on their hands similarly the wings of birds were very similar in their structure to the flippers of seals and so um comparisons among these species suggested that life wasn't static that that animals were not created perfect and immutable but that they changed over time the problem was that there was no mechanism for how evolution happened and there were a couple of different proposals but the one that we know and love today is the one that was proposed by erasmus star erasmus darwin's grandson charles darwin so charles darwin oh such an interesting story um charles darwin was a man of leisure he was uh fairly wealthy he didn't need to work but um he earned a degree in theology and his intention was good was actually to become a clergyman but prior to he didn't want to go into the clergy immediately after finishing his degree and so prior to entering the clergy he was asked to join the hms beagle on an expedition to chart the course of south america um and his job it's interesting his job on the on the voyage was to catalog all sorts of species like different plants and animals so he was meant to be the natural philosopher the natural observer for for the expedition but actually in a large part of why he was invited on the trip is because the captain just wanted somebody smart to hang out with and so um uh being a man of leisure uh charles darwin could afford to be his friend um but i mean it's not that he didn't do work he obviously did a lot of work cattle goring all sorts of species including those variations of the famous finches on the collapse gas islands so um he came home and started to think about the observed variations that he had seen and he started to think about artificial selection so this technique was something that farmers had been using for in breeding for thousands of years right so if you want fat cows you take the fattest cow and the fattest bull and you breed them together um and so farmers had recognized this idea of artificial selection of being able to neglect particular traits that they wanted um in their livestock and and make sure that they bred according to those particular desired traits so charles darwin was like okay we do this artificially maybe maybe the environment does it on purpose based on this he came up with his theory of how evolution occurs natural selection in this um in this theory the environment takes the place of the farmer essentially so the farmer is deciding which traits that he wants to see in animals here i'm going to anthropomorphize the environment and it's like the environment is like what traits do i think would be best for this environment um obviously it's not a thoughtful process the environment doesn't think about this it just is and obviously there just are certain characteristics that are going to be more effective in that environment than others so darwin in his theory of natural selection made three assumptions one traits are heritable two there is variation in the trait and three there is differential reproductive success okay now those three assumptions are maybe a little jargony they're a bit dense i want you to think about these statements for a minute what do these assumptions actually mean so for example if you were going to explain them to your grandma how would you do that how would you explain the idea traits are heritable i will tell you the answer but i want you to think about it for a couple of minutes and go through a little exercise first