Philosophy of Science: What Makes Scientific Knowledge Distinctive

[00:00:00][Music] Ladies and gentlemen, good morning. I welcome you to this class.

[00:00:27]Um I guess you are mainly from two different courses here. One part of the student population here comes from international horiculture and if you look around you'll see faces you've never seen before in your life. Right?

[00:00:42]These are the people from the other course. The other course is uh water resources and environment environmental management. Right? Is that correct?

[00:00:53]Okay. So um you can mix you may okay talk to the others. I do have a question first to those people from water resources. Do you feel more like scientists or more like engineers? Do you know the difference between scientists and engineers? Okay.

[00:01:15]So would you rather just tell me? It's fine with me whatever you are right. I can deal with you. But I would simply want to know do you rather feel as an engineer you know managing engineering about water resources or you rather feel like a scientist any votes are you from water resources no no from which course international oh yes so you are scientist anyway right yes but how about these other people with the water who who comes from water resources is you come from water resources. Are you a scientist or are you an engineer?

[00:01:56]Engineer. An engineer. Okay, that's fine with me. It's wonderful. It's very important because there's a difference between science and engineering, right?

[00:02:04]In some things and I have to know how you feel because then I can address you hopefully at least that I can talk to you in a way that you say yes I'm an engineer and I do understand what he means. I think it's nonsense but I do understand him. Right? So I try to address also those people who are engineers because they have a back different background and different expectations. Okay. So first of all you are all here for theories and methods of research. Nobody expects anything else.

[00:02:32]If you expect something else you're in the wrong room, right? And you should change the rule. That's uh clear enough.

[00:02:40]Okay. Now I give you some service. You get the slides here. the first page of the slides which you can download later.

[00:02:47]I tell you everything about it but you get it here because you may not have downloaded it. I uploaded it yesterday only and you can download it. And today we start with something extremely thrilling with the formalities right formalities are always full of humor. They're very interesting.

[00:03:05]That's why you came here to University of Hanover to hear something about the formalities. And I will start with the formalities first. And first the structure of the course which you may not know the structure of the course is the following. We will have 11 sessions with lectures. Lectures meaning that I'm going to talk mainly right and I may from time to time ask you some questions or you may interrupt me and ask me questions. That's allowed. That's fine with me. Okay. We got to talk a little.

[00:03:37]So we'll have first lectures and that'll be approximately 11 sessions with lectures starting today till the 12th of January of 2011. That's fine in the future but as long as I survive I will do these lectures. Okay. And then we will have three sessions with oral presentations of research projects.

[00:03:57]Okay. That will concern the MSE 13 students from international horiculture.

[00:04:03]Okay. Those from international horiculture. Are you from MSE 13?

[00:04:10]You are very good. Okay. You found the right room. You did a very good thing to come here. Okay. All right. And you will give oral presentations of your research projects. you all have research projects and the um horiculture students will give oral presentations and that'll be that's mandatory unfortunately for you but you will learn possibly something with it and that'll be on the 19th the 26th and this of January and the 2nd uh of February in 2011 that's fine in the future so don't worry about it right now I'm just telling you what's expecting you in the future next year right okay so now the people from water resourc resources. Don't believe you can be lazy. Okay, concerning that you have to do something as well and you have to do the following now. Uh, okay. First, I'm sorry. I first tell you what the presentations are and then I come back to the to the engineers and scientists from water resources. Okay, your job will be in the presentations. You have 15 minutes each. And believe me, it'll be 15 minutes and no minute more. Okay, it'll be really 15 minutes because we'll have six people in one session and we don't just don't have more time than 15 minutes. And in these 15 minutes, what you have to do then, you don't have to write that down. It's on the it's on the slides and it's uh you have the the print out of the slides. You have in five minutes maximum present your project, your research project. Not everyone may know your project and especially these people now from engineering, from water resources, they don't know anything about your project.

[00:05:46]They must know something about your project. You have got five minutes to present that. Then you have five minutes to make a connection of your project to the lectures. Now you have no idea what that means because you don't know what the content of the lectures is. But you will know after the lectures, okay? If you attend, if you don't attend and don't do anything, you don't know what the content is, right? So I may suggest that you come to the lectures. Then you know what the content of the lectures is. And by the way, you may have seen the camera in the back. These lectures are recorded and you can download them later and look at them. And I just gave the permission. You can even put them down on your cell phone. Right? So if you miss me, it's no problem. You simply pull out your cell phone and you look at me, right? And and listen to the lectures. Okay? If you don't miss me, it's fine with me as well, right? It's no problem. But you can do that. So um that is not an invitation not to come to the lectures. All right? But certainly it's a possibility but you shouldn't know that. Okay. So come back here five minutes for the project five minutes the connection to the lectures whatever that will be you will see that I've given this course for many many years and that was never a problem that people understood that what is what was spent there and then finally five minutes for discussion. Now this is a very tight schedule right and it puts some stress on you and that is intended right. Why is that intended?

[00:07:10]Whatever your job will be in the future, whether back in your home country, whether you stay in Europe, whatever you do, whether you stay in science, whether you go to the administration, whatever do whether you go to politics, sooner or later, you will have to be able to give short impressive uh presentations and you must that must be trained. And part of what I'm going to do with you during this presentations, I tell you something about presentations, how you do present effectively. I'm trying to of course show you how that how that works because I'm presenting here as you may have realized already but I'm trying to train you and it's very important that you get a good training in that and usually you don't get that at universities and it's part of my mission at least I take that to be my mission to train you there so it puts some stress on you that's right but you have to learn that and it's better you learn it here at the university because if you fail then the cost is not so high but if you fail then when you give go home to your minister then you say yes we have to do something for the environment or horiculture whatever then you better be effective right and we'll train that so but don't worry about it I mean I have done that many times and it never presents a problem to the students and then we had a five minutes discussion after 15 minutes is finished and the pressure is you have to keep these time limits okay all right but don't worry about it is in the future and as I said it never presented any serious problems now to the people from water resources as we don't have enough slots for everyone because um we have just one term. The second year students from water resources is that right? These are the second year students from the water resources. You are from the second year.

[00:08:52]Okay. So you know Hanova already a little wonderful. I don't have to introduce Hanova now. Great. Excellent.

[00:08:59]Okay. The second year students from water resources you have to give a written presentation of your research project. You all have research projects already, right? the older research project project from the first year. Is that correct? Okay. And you have to give a written presentation and also you have some pressure namely the written presentation. You have maximum one page where are we here maximum one page for the research project itself. I don't know your research projects and I must understand your research projects.

[00:09:31]Therefore, you must give me information about your research project. You've got one page, you know, not in not in these letters, right? Not in a in a fivepoint font, in a normal font, right? Please, my eyes, you know, I want to be able to read it. Okay? So, one page and then also in one page the connection to the lectures. Again, you don't know what that means, connection to to the lectures, but you will see that what that means once you've seen some of the content of the lectures. Okay? And here you have to hand that in by the 2nd of February 20112 noon. All right. One minute later and I won't accept it probably. All right. And the way you hand it in whether you do that by via internet or email or whether in physical writing we'll find out later. We can make compromises. Okay. All right. So that's the structure of the course. So for the first 11 sessions uh I will mainly talk um and you'll get some information about theories and methods of research and then it'll be your term.

[00:10:40]uh I can tell you we have had this course now for something like 12 years I think 99 we started 11 years and that is a format that has developed over the years and that's a format that seems to be successful uh meaning the training you are getting because you may be quite surprised I mean I'm a philosopher by training and a physicist and you may not have dreamed in your wildest dreams right when you came to Hanover that you are going to be exposed to a philosopher. I mean you are serious people, right? Serious engineers, serious scientists. You don't want to have anything to do with philosophers, right? Uh the fact is that the experience of these earlier courses has shown that you get here something which is also called soft skills, right? Soft skills are also important, right? you learn something and what you learn is probably or that's at least what I hope that you learn thinking about your science not just doing your science and doing your engineering but also think about it you know reflect upon it and make yourself become aware of certain aspects of your science which you do not become aware of often once you simply practice it but you think then about it and that's the idea here and also you get some training in the presentations now let's see how that works. That doesn't tell you very much because it's so abstract, but I'll show you what I mean. Okay, that's the structure of the course. All right, any questions regarding the structure? Yes, please.

[00:12:13]Because as you know that there are only 13 students but we are M 14 first year students. So as I see the regarding the M4 students, no the M they get the class next year.

[00:12:35]because we are 14 students and it is the compulsory course for us. Oh, you you're MSE 14 first year. Yeah, we are under MS 14 and it's the compulsory course for us really.

[00:12:50]Well, that's that's amazing to say the least. That's very amazing.

[00:12:56]um because I thought okay uh I'll tell you next uh next week uh because the the idea was that now this this course is given every year and that also only the the second year students are supposed to come. So are there any sec MSE 13 people are here as well right? All of them.

[00:13:17]Okay. All right. And the MSE 14 and who told you that it's mandatory?

[00:13:24]because you know like okay all right yeah that may be that there is a certain mistakes okay I tell you next next uh weeks 14 all right how about the water resources um you are all second year students right water resources second year all right how many are you by the way water resources students 115 eight eight okay all right all right I'll find that out I mean I guess you should take the class next year but perhaps something has changed and I'm not aware of it okay any other questions about the structure anyone confused about anything not yet okay we're working on it all right okay so more formalities Now the print out of these slides you can find on the internet right at stood IP do you know the stood IP everyone knows stood IP if you don't know stood IP you cannot survive right you commit suicide if you don't know stood IP right you shouldn't do that you're young people you shouldn't do that right so if you go to stood IP what you can find there is both the downloads of the uh uh slides in the format I've printed them out. You know, if you want to have another format for the slides to be printed out, tell me. I can also put six on a on one page or I can put two on one page. I thought this is a good format because then you can write comments on the right hand side. This is what the lines are for.

[00:15:11]All right. If you hate the lines, I'm sorry. There's no other format available in PowerPoint. So, there are lines because I heard my wife told me, she's also a professor. She told me that the students disliked the lines but I cannot unfortunately I cannot erase the lines.

[00:15:26]So uh but if you want to have any other format that's available to me in PowerPoint otherwise you have to give me another version of PowerPoint right but if you if you like another version it's no problem to upload them right if you want to have it two slides just tell me you know I'm not a mind readader not always at least and that I don't know you have to tell me if you want something else and please do tell me right this is a suggestion if you want to tell if you want to have a different format just tell me and then I'll try to do what I can do for All right. So the print out of the PowerPoint slides can be downloaded and also I was told that um in the in the worst case it takes two days that you can also download or look at uh the presentation at at the the lectures here in video and you can download it to your cell phone or whatever you want to do with it.

[00:16:14]Okay. Right. Now what's next? Here's a recommended book. I just tell you what you can do. It's not mandatory for you to buy this book and read it, right?

[00:16:27]It's the idea is because you've got many other things to do that in theories and methods of research, it's enough if you come here and um then work with the with the slides with the print out of the slides and listen to the lectures that's enough material, right? But if you want to do something else in addition, if you are interested in something and say, "Oh, that's an interesting subject and I want to know more about it." Right? then I recommend you this book Alan Chalmas what is this thing called science and there's nothing about engineering in that book if you want to know anything about philosophy of technology that would be the area then then I will find something out for you but um I just realize it now I have nothing in there but um yes um I will think about it as well and give you suggestions if you want to have more on that but that's a rather accessible book whereas other books in that area sometimes It's very difficult and for scientists and engineers not understandable not intelligible but this one is a good book and you can read it if you want as I said if you want what would be most um what would be the best for me is if I awake interest in you that you say okay that's interesting I want to read something about it but as I said it's not mandatory if it happens wonderful okay now the next week I will circulate a list for the oral presentation And then you have to write down your name and the date and the topic. But that I'll do next week. So don't worry about it because we have to have a list and we'll see whether it's whether you are 19 in the MSE 13 or 18 students. Probably you don't know that.

[00:18:05]I'll find out and then I'll see whether the last three sessions of the course will suffice or not. Now we'll have at the end a written examination. Okay, this is not a playground. this is a university and therefore we'll have a written examination at the end and that will follow the end of the term in the week just after the end of the term that's been the practice you probably know that um and that that's the week between 7th of February and 11th of February and probably it'll be on the 9th of February at 10:15 that's again a Wednesday at the same time right and probably in the same room so it's very easy for you you don't have to remember you just keep going as if the term continues you just come here the the difference being then that you get a piece of paper right and some questions and you say what's that that's the examination I'm telling you right now don't be surprised then okay right I've got it here you've got it in front of you that'll be the written examination and you should also know the grading the grading is the following 20% of the grading will be the oral or written presentation of your research project right that concerns everyone right everyone who wants to have this sort of certificate and 80% will be the written examination and for the written examination you are not allowed to take the slides with you okay because uh you may imagine that the written examination asks whether you have understood something on slides and you shouldn't copying that during the examination from the slides so don't be surprised if I say please don't bring the slides with you okay so I tell you everything right now don't be surprised later Good.

[00:19:46]Here's my email address. Email. Everyone knows what email is, okay? I do have an email address, in fact, and you may contact me, right? If you want. So, if you have trouble with your husband or with your wife or so, here's my email address. Uh, that's very easy. You could write to me and then I will try to answer. But please write in English or German, right? I probably don't know your mother tongue very well. Okay.

[00:20:14]All right. What else? I do have official office hours. Uh but they are very far away. I mean they are still in needaxon but it's it's very far away. Right.

[00:20:25]Don't bother about it. What I will do is I make a break of something like 10 minutes during the lecture. So at 11 or so I usually make a break 10 minutes only. You don't smoke during the break right? No smoking right for your health.

[00:20:40]I mean you are free people but uh all right it'll be 10 minutes uh and during that time I'm approachable. I'm also I'm usually here 15 minutes or something um earlier so at around 10 because I have to unpack the computer and everything and then you can talk to me. So it's probably not worth it that you come to my office hours or you can talk to me after the after the lecture. So I will be available that's easier for you. Uh, but if you really want to come to my office hours, here you go. Tuesdays in Moroni, back building, fourth floor, there's an elevator, but you're not allowed to use it, right? You have to walk up. I have a key, you don't have a key. All right? But here it's flat, right? You can approach me without using any stairs. Okay? So, but if you want to come, as I said, these are my official offices. All right? And that's it concerning the formalities, right?

[00:21:35]Anything interesting you found in the formalities? Right. Really thrilling. No. Any questions about the formalities? Completely clear, complete orientation about everything. Wonderful. All right. So, let's start. I start with an introduction. Okay. That's very traditional, but it's useful to start with an introduction. And the introduction is the following. that I tell you what the fundamental question of general philosophy of science is.

[00:22:10]You've waited all your life to hear this fundamental question, right, of philosophy of science. That was a joke. Okay, of course you didn't wait. You are quite surprised. Why should I care about the fundamental question of general philosophy of science? Maybe you are questioned now.

[00:22:29]Well, you should care because that is at least as long as you stay in class because that is what we are dealing with here in this class. The general title is theories and methods of research and these theories and methods of research.

[00:22:45]They try to answer a certain question and the question belongs to a certain discipline and that discipline is called philosophy of science. Right? It's just called philosophy of science. Don't worry about it. is just a name, right?

[00:22:59]And that discipline deals with a certain question and that's the question that we deal with in this class and that is what is science? A very very simple question.

[00:23:10]Okay? And we are dealing with that question. We want to understand what science is, right? And theories and methods of research tell you how science proceeds in order to get the results that science wants to achieve. And I include here engineering because engineers have a different sort of procedure than scientists usually there there are very important differences especially when engineers interact with scientists there are quite a lot of misunderstanding sometimes and the engineers thinks about the scientists and the scientists think about the engineers um and it's sometimes difficult because they have different thinking patterns at any rate although I only write here what is science what I mean to say is that I include the engineering um and you'll at certain points when I when I specifically address engineering. Okay. What is science? That's the general question.

[00:24:02]You may ask this question in different terms. Why is scientific knowledge different from other forms of knowledge?

[00:24:09]For instance, in being more reliable. I mean, why is scientific knowledge better than other other knowledge? Well, most people think because scientific knowledge has some certain specific qualities. For instance, being more reliable. I mean, why are you here? Why do you spend your time? You come from countries in which probably the weather is much better than here in Netherax and it's much nicer and you decided to come here, right? And sit here in a rainy day and listen to me. Why are you doing that? Well, I guess because you believe that scientific knowledge is something.

[00:24:45]Well, you want to have more of it, right? You want to understand something either concerning your water resources or concerning your plants or your whatever it is what you are doing. you want to understand more about it and you want don't want to have the say the traditional mode of knowledge that possibly some people back home still practice but you say no I want to have scientific knowledge right I don't want to have everyday knowledge I don't want to have voodoo knowledge I want to have scientific knowledge and why do you want to have scientific knowledge well you probably don't really know right but I guess you have the hope that scientific knowledge is somehow better somehow specific it's something else, right?

[00:25:25]Something you want to rely on, right?

[00:25:28]Most of you probably have some sort of cultural tension, right? Because this scientific knowledge is knowledge generated and mostly practice in the western countries, right? In the industrial world and you, some of you come from countries that are less industrialized and scientific knowledge is less pervasive in these countries.

[00:25:46]And you decided even I mean you you took a very brave decision. You said, "I want to have more scientific knowledge. I want to go. I have to go in order to get the best education. I have to go to a different country. You choose Germany.

[00:25:58]You choose Netherax. You choose Hanover.

[00:26:01]And now you're sitting here. So you are living proof that you believe in a specific quality of scientific knowledge. Otherwise you wouldn't be here. Right? But the question is and that's the question of this class. I mean what what is it you know what is specific about this scientific knowledge? Why is it different? In which sense is it different? Right? Can we understand why scientific knowledge is different and better than other forms of knowledge? Right? That's the question we're addressing here.

[00:26:30]Okay? So, it is something that does concern you. Right? Even if you can't use it immediately in your research project, you will find out you can't immediately do it. But the experience tells us from this class from the last 10 years that it is useful to you that you start thinking about science and you learn something. Okay, that's a program and promise. Don't believe promises. Uh but you'll find out yourself. Okay, so that's the question. Why scientific knowledge different from other forms of knowledge? For instance, in being more reliable or whatever or more systematic or whatever it is. All right. Or in other words, what are the characteristic features of scientific knowledge? What is what is the specific specificity of scientific knowledge? Why? But in what sense exactly is it different from other forms of knowledge? All right. Now, what I'm going to do, how I tackle this question is not that I simply tell you all the truth about science. Right? The reason is there is with the relevant people here philosophers of science or scientists themselves there is not really a wide consensus exactly about what science is right that's different say if you look at evolutionary theory or if you look at hydrodnamics if you look at hydrodnamics there is a consensus about everyone about the fundamental principles of hydrodnamics right? You have flow equations or whatever and you have conservation laws and whatn not or if you look at biology I mean there's all really I mean there are a few very strange people but I mean everyone really being a specialist in biology accepts evolutionary theory nowadays yeah there are some people who don't but they're rather strange somehow at any rate so there is a consensus if you look at many areas of engineering or many areas of science there's a characteristic feature that there is a consensus that people come to agree how that works or what the basic principles are and that is different in that area in which we are moving philosophy of science and there is not really a consensus there are different answers and um what one has to learn if one thinks about science is to cope with this variety of answers because you don't get simply one answer and you can take it home and say I know the truth about science that's unfortunately not not so easy it's such a tricky and difficult subject that people don't reach an easy consensus but still one can talk sensibly about it and that is what I'm going going to do and what I'm going to do is I'm will present you four specific answers to this questions what science is and what specific is about science to these questions and which have been given during the last 100 years so what you'll hear then is a panorama so to speak a spectrum of answers and we're going to discuss these answers you know what their strengths what their weaknesses are and that is the sort of training you should get here namely thinking about science and thinking about arguments and then trying to understand the the different positions and then finding arguments why this position is better than that position and so on so you it's it's a sort of training to think about science that is what you're getting and I'm doing that in presenting you four specific answers to these questions and now I I present you simply the titles of these answers I don't expect that you understand these titles titles inductivism. Have you ever heard the word inductivism in your life?

[00:30:02]Who has heard the word inductivism? Have you heard about the problem of induction or something? No. Very good. So you it'll be full of surprises what you'll hear here, right? Many new things and say, "Wow, isn't that interesting or isn't that boring?" Whatever.

[00:30:17]Inductivism, deductivism, paradigm theory, and systematicity theory. So you don't know anything what that means.

[00:30:24]These are just the titles, the names of certain positions. And I'm going to explain to you these positions. All right? And what I'm going to do, I'm telling you right now because you will be surprised in the in the course of that uh class, I will first present these answers as persuasively as possible. So what I want to do is when I talk about in this position inductivism what I want to achieve is that once I finished my presentation of that position that you say wow now I know what science is right that's the right answer and then you say wow yes I'm an inductivist I tell my mother write her an email right I'm an inductivist now ma'am it's wonderful I know what science is right that is what I try to do and And I will try to criticize right that position that inductivist position and show you that well you first be completely convinced and you see wow there are critical remarks oh damn it oh that's difficult oh it doesn't really work right and then you are very disappointed right and again write again to your mother or your sister and say I'm very disappointed mom inductivism doesn't work okay and then I'll do the same again then I present you deductivism because deduct Inductivism will be an answer to the problems of inductivism. Right? Deductivism is a different position. Again, you don't know what that means. It's a different position that was developed because of the problems of inductivism. And deductivism said, I can heal, you know, all these problems here. I can, you know, I have a good medicine against it and I tell you really what science is, right? And I'm going to tell you what what the answer of deductivism is. Such that at the end of the presentation of deductivism says, "My god, I'm so happy that I'm not an inductivist anymore because now I'm a deductivist and now I know the truth about science."

[00:32:20]Right? Um yes, but then I'll start the same game again and I'll show you what the problems of deductivism are. And then you get counterarguments against deductivism and that I do four times.

[00:32:31]Right? So the training you are getting is that you start thinking and I'm trying to really seduce you into inductivism. I'm going to seduce you into deductivism by presenting it in the in the strongest possible form I know of and make it as as plausible and and uh um seductive and convincing as possible and then I will criticize it afterwards.

[00:32:52]And that's the idea you know of of playing this sort of dialectic as one says in English that dialectic you know of of arguments counterarguments and and pro-arguments and counterarguments and that is why we do this class you learn these positions right that if you find sooner or later in the literature or in discussions you find these the these positions then you know what these positions mean and also you know arguments about these positions why they could be good or what the weaknesses and so on and so forth, right? Uh so I I summarized that after attempt to present these answers as persuasively as possible, criticism of them is raised which forces the development of new answers, right? And that's the idea. So this is really different from science, right? That is not a procedure you have been you have experienced in your life in science because in science the usual thing is that you you learn a new theory or set of devices or a new model or whatever it is and the presentation mode of presentation is of course that you learn it and the idea is then you can use it right and that is because in the sciences you have at least often not always but often you do have a consensus and it is quite clear that you can use the theory it makes sense to use the theory or model or whatever it is or procedure, measurement procedure, whatever it is or optimation procedure, whatever it is and therefore that that there is not no need for that sort of of um procedure to discuss something. But as we are in this field where we do not have a consensus about what science is on the other hand, we are interested in that and it's useful for you to have this sort of discussion, I use this mode of presentation. Okay, again this is still a little abstract but I'm just telling you don't be dis too disappointed uh when you know I first I first behave as if I was really an inductivist and I tell you every truth about science by telling you inductivism and then two two hours later a week later I say you know inductivism doesn't work no no way okay so I've not changed in the in the meantime it's not that I'm schizophrenic or something it's just normal right so Um, I'm just telling you, you know, it's it's some somewhat different than the other classes attending. All right. So, we start with inductivism. Any questions concerning that procedure? Is it at least a little plausible why that could be done that way? I mean, it's very abstract. You cannot really imagine what's going on.

[00:35:20]Is that plausible? Any questions about that? Okay. Then let's start with inductivism.

[00:35:30]And I start you will see that I'll start all these lectures that I first give you the basic idea right so to speak in one sentence that you understand what that position what what the main aim or the main thrust of of such a position is um the main idea and that idea will then be a little be developed and such that it becomes you know more um extended and then well we'll see we go to the to the criticisms the basic idea a of inductivism we have to start with something with an observation which is rather simple but I have to make it explicit here because otherwise we don't understand the procedure of inductivism and the main idea of inductivism it's the observation that in science and engineering we find singular statements and general statements right singular statements general never heard that possibly I'm going to explain to you what are singular statements singular statements for instance now I try to use examples film your area right um I have I told you already I'm by my original training is in physics so I'm not a water engineer I have no idea well I read a little but I don't know very much about it I know a little more about um horiculture science because um I heard so many presentations by the horiculture students during the last 10 years so I learned a little about it so if my examples are really stupid then please tell me if if the if the water. People tell me, "Look, this is nonsense." Uh, well, I looked it up in the internet.

[00:37:03]There are lakes that are contaminated by pesticides and heavy metals, right? Am I not right? There are lakes. They are heavily contaminated. So, now you stand, imagine you stand in front of such a lake and then a water engineer says, "This lake is contaminated by pesticides and heavy metals." That's a singular statement. a singular statement because you speak about a singular object in front of you right that lake and you say something about that lake okay now the horiculture people will say I don't understand this example right because I'm not a water engineer am I not right not really okay I have a now this is the example for the horiculture students right this plant has nine leaves yeah you imagine you have the plant in front of you you count the leaves and then you say this plant has nine leaves. I know it's sometimes important to count the leaves, right? Not for all of you. Those who do economics of horiculture of course don't care about leaves at all.

[00:38:06]They see money, right? For instance, export, import, you know, gross national product, whatever. Okay, but you can't I mean I think everyone can understand this one. This plant has nine leaves.

[00:38:18]That's a singular statement. Why? Not because the number nine is here because you talk about that s that plant in front of you right about this singular little thing that plant or big thing maybe a big well if big things have more usually more than nine leaves but imagine winter time right then the big oak may have nine leaves we'll come to that state I'll give you examples then when you look out okay here are examples both for the engineers and for the um horiculture students all right back here leaves. Going to concentrate here on that. Uh, this plant has nine leaves.

[00:38:54]That's a singular statement. Now, true singular statements express singular facts. If a if a if a singular statement is true, then it expresses something and expresses a singular fact. Namely, for instance, this one expresses the fact that the lake is contaminated by pesticides and heavy metals. Right? And the other one expresses the fact that the plant has nine leaves. That's very simple. But it's it's important to to be aware that you say, okay, what's a singular statement? Oh, if a singular statement is true, then it expresses a singular fact, right? A fact like this plant has nine leaves.

[00:39:35]Okay? Sounds very trivial. Now in science and engineering the singular fact the singular statements that you find there often not always but often express observable and or measurable facts. So if you do an analysis of a certain lake for instance and you are asked as a as a water engineer you say look this lake it's very funny that the fish are all dead in this lake. Isn't that an accident or what what happened?

[00:40:04]And then you say, well, very simple. We just look at the contamination of that lake, right? And you measure the pesticides and you measure the heavy metals in there and you find 50% is not water, but heavy metals, for instance, which is a very high concentration. I know, and I'm exaggerating a little.

[00:40:21]Okay. Then you say, okay, I have established the fact that this um lake is contaminated by heavy metals. And you can express that singular fact. And you establish that fact by measuring them or by observing them. So for the hoticulture scientists, you you establish that fact that nine leaves that you observe it and you count in them and you say yes here that's the fact right? So many of these singular statements that you find in these areas both in science and in engineering they are singular statements that express observable facts. Not all facts are observable. Right? If you go to cosmology, right, that's not a a field that you study here in cosmology where you study the the history of the cosmos.

[00:41:09]Then the today cosmologist, today's cosmologist, they state the fact there was a big bang in the beginning of everything, right? That's a fact about a sing that's a singular statement about a singular fact. Well, if it is a fact, I mean, people believe it. Okay? And that's of course not observable. You cannot you cannot ask a cosmologist, oh let's go out and and let's observe the big bang, right? That's not possible.

[00:41:37]Why not? Well, was in the past, for instance, and if you could observe it, you wouldn't survive it, right? And you didn't Well, it's a Okay, it's quite clear. Does everyone know what the Big Bang is? It's a rather big bang, right?

[00:41:52]It's very loud. Is it loud? No, it's not loud because you have no air, right? Okay.

[00:41:58]All right. In science and engineering often express therefore I say often observable facts and that will be the starting point of the position. I'm not telling you because I want to impress you what I know about singular facts that all because that's the basic then of inductivism because that'll be the starting point of inductivism namely the singular statements that express observable facts. That is where I move to. Okay. And therefore I have here this distinction between the singular statements and the general statements.

[00:42:28]So that is the case and we will see that that will be the starting point of that position that I'm going to develop that is called inductivism and you still don't know why this is called inductivism which is fine. All right. So these are the singular facts. Now in this case if you if a singular statement expresses an observable fact then it's easy to verify the statement. To verify means to find out the truth of the statement. Right? It's very easy because what you do well you observe or measure and you will know right. So if someone tells you look this lake is very contaminated or if if someone says the river um l is very contaminated by this and that by pesticides you say well I don't know perhaps he's right perhaps he's wrong and if someone says well please establish the fact whether the line is um contaminated by pesticides and heavy metals you say very easy you know you pull out your measuring instruments go to the lin and measure it and then you establish it said well the concentration of this this and that and that that is so high and high yes that kind that that um counts as contaminated. Therefore, the line is contaminated. So, it's no big deal really to find out whether a singular statement is true or not in many cases if it is a singular statement about observable fact or measurable facts. But what you do is simple you go there and observe it or you go there and measure it and then you know, right? So if someone claims this tree here has uh well you don't see that if I point out there this tree here has 1,400 leaves right in principle you simply go out you know spend your lunch there don't eat don't drink and count the leaves right and then you say no it's not 1400 it's something else 1200 or whatever right but in principle you know exactly what to do if you want to find out whether a certain observable statement uh is true or not you simply go there and you measure and observe and that's very simple with singular facts. It's very simple because in singular facts you have one object you have to look at right one the lake in front of you or the the the river line or that particular tree or a particular plant you look at it and observe it and measure it and then you know right and that's comparatively simple right but science isn't that simple because it does not only contain singular statements it also contains something else namely different general statements in the sciences and the question why I made this distinction here between singular statements and general statements is that the procedure to find out whether statements are true. These procedures are different for singular statements and for general statements.

[00:45:13]Right? And as we are interested in science whether it's true and whether it's good knowledge and so on and so forth, we are interested in how do the sciences find out whether something is true or not. And because the procedures are different for singular statements and general statements, I made the difference between these sorts of statements. Right? And the point is that the problem with finding out whether a scientific statement is true or not, an engineering science statement is true or not. The problem does not really arise with the singular statements because they are fairly often quite unproatic. You simply measure or simply observe right the singular case. But the problem is when you come to the general statements right and the general statements present problems and they these problems then provoke this position which is called indepism and that therefore I make this distinction just that you know what I'm doing here and why I'm doing it. Okay. So um in earlier classes people asked me I should say more about these terms that are going to come now the terms like hypothesis theory model and so on because you use these terms but you don't really know what they mean very often at least people told me students told me therefore I did that for the first time this is now a a premiier right you are the first one who sees that nobody else has seen that before isn't that wonderful well let's see whether it's good then we'll find There are different kinds of general statements in the sciences and I want to talk about these this difference of the general statements.

[00:46:45]Now let's see whether yes there are things like natural laws. All of you heard of natural laws of course because you have you have studied natural science and engineering. Natural laws like Newton's law of gravitation. That's a general statement. It tells you something about all cases of gravitation. Right? That's the idea of a of a natural law. It tells you something very solid. And if you want to remember that means the force is gamma. That's the gravitational constant. Then mass 1 time mass 2 divided by the square of the distance. It tells you that's Newton's law of gravitation as you have all in the slides. Right? If you copy that, you copy it. It's on on the slide. It's in the print out. Okay. Have you seen it?

[00:47:30]Have you got the print out? Right. It's there. Yeah.

[00:47:35]Oh, I'm sorry. Is that already? That's the number seven. Okay. Yes, you can download it.

[00:47:42]Okay. I'm sorry. Sorry, I didn't realize we are Reddit number number seven. I only gave you six, you know, in order to force you to go to stood IP. No, you can download it there, right? Okay. So, but uh yeah, so you may have may take notes uh now, but at I I promise it's it's there. We checked it just before. It's there on stood IP. You can download it un unless the main frame breaks out.

[00:48:07]Okay. Now, okay. Uh so this is Newton's law. Who has not never heard of Newton's law of gravitation? Very good. You are too shy to show me who haven't heard. Anyway, now the point is with natural laws when the when in science something is called a natural law like natural like Newton's law of gravitation, it's first of all of course it's a general statement. You don't say anything about something very specific. You don't talk about the earth or the sun or for instance this little instrument has also gravitation and it gravitationally interacts with the earth is I if I let loose now then we'll see the gravitational interaction very clearly um they are supposed to be certain when when scientists natural scientists speak about laws natural laws they think they really know the laws and the law is certain and it's usually or very often they are exceptionalist laws and you simply know that they are true Right? They are supposed to be certain. Natural laws are general statement that are certain. Okay? Then we have something else. Natural scientists don't only speak about natural laws. They also speak about theories. In other word, theory means different things in different contexts.

[00:49:21]It's not that it's always the same thing what you mean when you say theory. And what does that mean? Well, it may mean very wellestablished very general statements like say Darvin's theory of evolution or quantum theory. I mean here you even see theory Darin's theory of evolution. Right? So this is something extremely general. Darin's theory of evolution is supposed to apply to everything living on earth. Right? Just everything. everything was evolved according to mutation and selection to to put it in in a very short form and that Darin's theory of evolution or quantum theory if you look at things that are rather small with low energy then with little energies uh say atoms molecules or something then quantum theory applies and the idea is that quantum theory applies really absolutely exceptionlessly right all the cases of molecules atoms or so obey obey the laws of quantum theory right that's the idea the same with Darin theories so we have we we speak about theories in the natural sciences very well established and very general statements right very general meaning here in Darin's theory of evolution just every organism is supposed to have evolved according to Darin's theory or in quantum theory just every sort of atom every sort of of of nucleus every sort of molecule obeys the laws of quantum mechanics That's the idea of theory and very wellestablished.

[00:50:56]So if you today say a biologist and you say well I don't think that Darin theory is right. I think that's nonsense. I mean better go home right I mean all the other biologists will say sorry wrong class. Okay it's so well established same if you are physicists that say no no kind of theory is false. I mean it's very simple. Then people will say you're crazy right? You don't understand what you're talking about. So these are very well established and you have of course uh these this is one sort of meaning or one way how to use the term theory for these very wellestablished very general statements like Darin's theory of evolution. There are other theories of course but these are just two examples.

[00:51:38]That's one way of using the word theory.

[00:51:41]But there is another use of theory and that means really something different but we also call it theory and that's general statements about which you are unsure. So it's just the opposite. Here you are unsure and here it's very well established when you say it's just a theory right if someone says you know blah blah and then someone answers but you know this is just a theory meaning well you can't be too sure about it you know this is what what you think and that's also what is called a hypothesis you know when people say that's a hypothesis then you know you are unsure you play around with it and you say yes it's a hypothesis is I I I look at it, I consider it, I may analyze it, I may do some research on the basis of that hypothesis, but by saying it's a hypothesis, I'm expressing that I'm not sure of it. I I it's not certain that it is true. Right? And that is also a use of of theory. It's just a theory or hypothesis. By this term, you express your your possible doubt about it.

[00:52:48]You're not saying it's false, but you say, look, I don't really know whether it's true or not. And that is why we we use in science then the the term hypothesis because we very often deal with with general statements about something and and we are not yet sure whether it's right. So I guess I mean isn't it in horiculture science you have to formulate when you do your outline of your research project you have to hypothesis you know that's the that's the idea the hypothesises and then you go to next section is then what is it the testing or methodological procedure methods or what how to test the hypothesis right and if you admit that you have to test the hypothesis of course you admit that you are not completely sure that's true but but the point is that you say well that's interesting Right? If if for instance sunlight now influences the growth of these plants in such and such a way that's my hypothesis let's test it.

[00:53:42]Right? And then you play around with the sun and play well that's a bit little difficult but you may play around with artificial light right and then then look what what the the the impact of the light is and so on and so forth. So that's an hypothesis something you you play around with. You may show that it's true or you may even show you may want to show in other context that it's false. But the point is that you are not sure about it. Right? That's that's the idea of hypothesis. And sometimes you use the term theory in the same way. But be careful. It's really very different when you use it. It's just a theory. You don't mean something as solid as quantum mechanics, right? Certainly not. But you want to say, look, I'm not really sure whether it's true and and I want to consider it. I want to test it or I want to confirm it or justify it, whatever.

[00:54:28]All right? So this is the term theories but there are here for instance oh this is a wonderful example for the horiculture people my theory or my hypothesis is that plants of species species X are not seriously affected by a change in the environmental condition why right that is something where the horiculture students find themselves you say yes that sounds familiar yes wonderful not for the economists right among you perhaps I have an example data for the economists as well. Right? There are so many different people here. So I can't I can't do everything for everyone at the same time. Right? So you have my theory is that and that means then yes you know something about these plants of species X and and you think you say well I guess it's this is the case. They are not seriously affected by a change in environmental condition Y. And then your supervisor tells you it's so devise an experiment. Tell me what the methods are to test this hypothesis. And then you say okay I put 400 plants there and then I systematically change environmental condition why and then I look and then I count the plants what is the effect and blah blah blah. All right. So this is the dealing with hypothesis because you don't know whether they are true and what what you want to do is you want to establish well they're truth or falsity is a bit a little high but at least you you want to have arguments to defend the hypothesis or you want to have arguments to attack the hypothesis. Right? You want to deal with it whether it's more true or less true or true or not true or something like that. You want to evaluate it according to its one could say truth content whatever that is.

[00:56:10]Okay. So this is theories and hypothesis. These are terms that are used in science and we are now a little clearer about what they may mean. I continue five more minutes and then we have a short break. Okay. And then we have something which you may hear probably in engineering as well and in the sciences that one speaks about jularities or empirical regularities. You also find that of course in the social sciences.

[00:56:37]Are any social scientists here as well?

[00:56:39]People with the social science training. Okay. So you learn something about the social sciences as well. Oh, we have a social scientists in the back.

[00:56:48]But that doesn't count today. All right.

[00:56:50]Empirical regularities. And these are in principle these are general regular relations. It's a general uh well here it's a plural and here's a singular I'm sorry a general regular relation between different variables right you have a connection between variables and that's regular. So if you change variable A a little and then variable B changes in a certain way and the connection between the two is expressed by the regularity.

[00:57:17]Right? Is that a way engineers speak as well about regularities? Engineers sometimes well if you have a table and you have say variables on one side and the connect the dependent variables on the other side you call that you call that a table probably just a table function or whatever. Yeah function. Okay. empirical regularics that's a term that's also used in the sciences in different uh branches. Uh and finally there is something which is called a model that a model is also a general thing. It applies to many different cases usually and a model is also such a general statement and here it is typically a simplified image of a general relation among different variables. Right?

[00:58:01]So I come to an example later. Um for instance, one speaks about model organisms. Um any idea? Can someone give me an example of a model organism in biology?

[00:58:19]Right? It's a plant, right? And there are of course animals as well where you have that that's the specific plant this model or you have other models. But these are I mean they are somehow they are simpler than other plants. That's the belief at least. So if you want to experiment on plants and you have complicated plants then you say okay let's first experiment with these model organisms because they exhibit then in a in a simpler way what we want to understand right and that is model organisms. The idea is this is of course not an image of a general relation but a sort of image. It's in model organisms that you can can investigate something and you hope then that in the model organism it's simpler than in other cases but you have a hope of course that you can transfer that that something you learn about the model organism can be transferred to other organisms that's an hope that's sometimes justified sometimes not that's not my point my point is here simply that you become aware what the term model means it's another thing is when you speak of a model of an economy an economy is a very very very complic economists here as hopefully from the horiculture science.

[00:59:27]Yes. Good. Economists. So when you speak a model of an economy, you say, okay, I mean there may be a million households and 10,000 firms and 15,000 governmental agencies that all interact and it's absolutely it's a mess and complicated and you can't say about it. You can't say anything about it. So you say let's make a simplified model, right? We make a model of a million households and they have all the same preferences for instance and we model the the um governmental uh governmental agencies.

[00:59:58]We model they they have laws and they restrict the actions of the the uh of the households and so on and so forth.

[01:00:04]You simplify right? You make a simplified image a simplified image of the generary relations or if you take the model of a lake for instance if you have a certain lake and this is now for the water people. If you have a lake, I mean the lake is very complicated. It has a very complicated topography and you want to understand what the what what happens with the lake and you have outflows and inflows and evaporation and you have uh minerals and you have what not and damages and so on and so forth and you can't you can't if you look at the if if you look at that lake you you can't really have all the details. So what you say let's make a model of the lake. Let's assume the model is just you know round right it's not of course in reality it's not round let's make it round and it's got constant depth right 15 mters period and then I've got the volume of the water that I want to investigate and we assume it's just water in and we have one inflow one outflow and and evaporation rate such and such you simplify and what you do really is you have general relations and then you say yes the general relations are then with the inflow and the outflow in this model is such and such and then you model the lake and you have general that is the very important point here a general relations. So as I said we have in the sciences and in engineering we have very different sorts of things which are general statements. The general statements may express theories, they may express empirical regularities, they may express models. Um uh yes now the important point is why I made the difference I told you earlier between the singular statements and the general statements is this that the general statements that means laws theories general hypothesis regularities and models they cannot be verified in the same way as singular statements and why not because they refer to indefinitely many facts it's not just one fact but very I give you an example. Okay. Now, okay, I first tell you that this is problematic. The so-called generalization of singular statements to general statements is problematic. You are not taking about a singular case where you can make a decision what is the case by looking at it and measuring it because you talk about many many cases and just look at the following case. That's a standard example. For example, consider the generalization from the observation of some finite number of swans that are white. If you observe, so you go to the I don't know where the swans are in Hanover in the zoo for instance or perhaps on the line and you go there and you observe the swans and all the swans are white and then you say, well, I've seen now 15 of them. All swans are white. Okay, is that a good generalization that all swans are white?

[01:02:59]No. Who comes from Australia? Nobody.

[01:03:02]But you've read it. There are black swans, right? It happens to be the case.

[01:03:06]They are just black swans. So the generalization from your observations that you do here in Europe, unless you go to the zoo where they have black swans, but if you just go to the rivers and to the lakes, say in Germany, and watch the swans, and then you say, "Yes, I've I've seen them, you know." And now I give you a general hypothesis about swans. Namely, all swans are white. This is tricky because you haven't seen all swans, but you talk about all swans, right? And that's the problem with the general statements because you talk about all sorts of things with the general statements, but you haven't seen all of them, right? And that's the problem, right? But what happens is in science that we want to have general statements. I tell you after the break why we want to have the general statements. We need them, right? It is not enough in science just to say okay that's too dangerous let's forget about general statements only talk about this plant and that plan I give it names this is Anna this is France and this is Jim that's not enough right your supervisor would be very unhappy with you if you say no I refuse to talk about general things I only talk about this particular plant say no sorry in science we have to have general knowledge about plants about a certain species for instance because we want to not export this particular little plant that is dead in three years from now but we want to have these species of plant and want to look what it does in that environment you know all sorts of them all singular specimens of that species so we are interested in general knowledge I tell you more about that later so we have to have general statements but we have a problem with the general statements you know it's difficult to find out whether they are good statements whether they are right whether they are true right because there are so many cases and you see here when you simply say well look at the number of swans that you found out their color. Yes, but you can make a mistake here, a grave mistake that you say all swans are white and it's just not true because there are black swans.

[01:04:58]You unfortunately haven't seen any one of them. Okay, so there we now approach that problem and uh okay, that's good enough for now. So we make a short break now of say 8 to 10 minutes um and then you please come back and then I continue.

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