When I was younger, in my teens, I started to discover my love for the sciences. I was fascinated by Biology and Physics and I think I must have driven my teachers crazy with my constant request for “proofs” and evidence. I liked science so much that I even included chemical formulas in my literature essays. Instead of saying “The water waves are gently moving in the sunset.” I’d write “Waves made of H2O are gently moving in the solar spectrum.” My English teacher then responded, “Don’t forget about the H2SO4 (sulfuric acid) which is dissolved as well!”. An then I didn’t feel as bad about the bad mark on the test anymore… Now I am teacher myself and occasionally I meet some students who remind me very much of myself. They are constantly confronting me with the words “How do you know that?” – always eager for empirical, scientific evidence. They want to see things before they believe it. They want formulas. They want cause and effect relationships. Without having been aware of it, I myself as well as my students, were followers of a certain philosophical school. We were “Positivists”.

Now we’re are right in the middle of the topic. What is that: Positivism? Essentially a positivist is a person who only accepts sense perception or experience as the only source of knowledge of the world. A strict positivist will reject intuition as a way of knowledge, for example. Positivists are looking for positive empirical evidence for a claim (this is the reason why they are called like this). So if I claim that water freezes at 0°C, then I have to find one positive scientific proof for this claim. I have to use a thermometer to make the measurements, and when it indeed freezes at 0°C (I can see this with my eyes – sense perception), then the statement that water freezes at 0°C was proven correct. This is the so-called verifiability criterion. Only statements that you can verify as true or false are meaningful. As a side remark, this is quite different from the principle of falsification, which states that you can only disprove statements but never prove them correct with certainty, but more on that later.

A logical positivist will also consider Logic a useful tool to organize the knowledge. But they will not accept emotions or intuition as an acceptable way of knowing. For a logical positivist, emotions are a “no-go”. You can not say “I know that stealing is wrong because my conscience tells me so.” Conscience is not empirical, and therefore not an acceptable source of knowledge. If you make a certain claim, then you must be able to support it with sense perception as a form of evidence. According to logical positivists, claims than can not be supported by empirical evidence are meaningless. They are not necessarily wrong. They are simply meaningless. For them only statements that can be proven true or false are meaningful. For them the statement “A human has three heads” is meaningful, because you can show that the statement is false using sense perception. Just count the heads of the people. The statement “stealing is bad”, however, does not reveal anything about the world, it is simply a command on how to behave, and you can not prove it right or wrong using empirical methods. For the logical positivists, metaphysical statements, such as “The world has a purpose” were even worse. These statements can not be verified and are therefore (in their view) completely meaningless. They don’t add anything to our understanding of the world. Maybe they are right, maybe they are wrong, we don’t know, so better not deal with them.

Now back to my TOK students. I’ve often heard them say something like: “The problem with ethics is, that you can not prove it scientifically. Everyone has different ethical standards and we can not prove the different ethical views as right or as wrong.” Yes, correct. How do want to scientifically prove that stealing is morally wrong? Ethical statements are not falsifiable and therefore inherently not scientific. But why are so many people always looking for a scientific, empirical proof? Why is empirical evidence considered to be so much more valuable than other ways of knowing? I can not empirically prove that my parents love me, but it is still of very high importance to me and just because we do not have empirical evidence does not mean that the statement “my parents love me” is wrong.

I am currently reading a book with the title “The Vienna Circle”. And I thought that I’ll tell you a little about this circle and the views that they had. The Vienna Circle was a group of intellectuals, philosophers and scientists, who met from 1922 to 1936 in various coffee shops in Vienna, Austria. They met there once a week and to discuss various philosophical topics. They were the ones who were really driving logical positivism, and a scientific world view forward. The members of the circle all shared a common view. They considered the current philosophical debate that was going on at that time as pretty pointless and meaningless. In their view, many philosophical claims at that time could not be verified. Therefore they decided it’s time for a reform of ideas.

The members of the Vienna Circle were very much concerned about the meaningfulness of statements. For example, they would say that the statement “The world has a purpose” is completely meaningless, because there is no way that you can test this. Also the statements “God exists” or even “God does not exist” are considered meaningless by logical positivists, because you can not prove or disprove this scientifically. It’s important to know that they would not consider these statements necessarily wrong. They simply would consider them without meaning. In simple words, positivists have a very “scientific” world view. They do not like to debate issues of ethics, morality, metaphysics (“What is the true nature of the world?”), etc. because you can not use your sense experience or scientific measurements to test these claims. The Vienna Circle stopped pretty dramatically in 1936 when the founder of the circle, Moritz Schlick, was assassinated by one of his own students. The motifs were, at least to a certain extent, political in nature.

Some remaining members of the Vienna Circle realized that there is a problem with their view. They always stressed the importance of sense perception, but they also realized that sense perception is also very subjective in nature. After all, the brain interprets the information it receives from the eye. How can science be objective if it is based on subjective sense experience? I think you already noticed that those folks were spending quite a bit of their brain power discussing Theory of Knowledge related concepts.

Several members of the Vienna Circle, especially Otto Neurath and Rudolf Carnap, now started to promote the concept of physicalism to overcome this problem – another new term. Now, what’s this? Physicalism is the view that all events of the world can be explained by the laws of physics. I best give you an example. You are about to write a test and you are nervous. This is a feeling that you are certainly familiar with. It is a psychological phenomenon. But what is this, nervousness? The feeling can be explained by the hormone adrenaline flowing in your blood. So, we reduced a feeling of nervousness (psychology) to a hormone (biology). The hormone is involved in chemical reactions with your body cells. So now we are at the level of chemistry. Biology is therefore based on Chemistry. And chemical reactions can in turn be explained with the help of quantum mechanics, which is physics. So your nervousness before the test can be explained using physical laws. A physicalist will therefore consider physics as the unifying or most basic science. The world can be explained with the help of physics alone. What about thoughts and ideas? A physicalist would say that thoughts and ideas are formed by your brain cells and the function of these cells can again be explained using brain chemistry and physics.

What is the situation concerning Logical Positivism today? In brief, Logical Positivism, as was promoted in the 1920s an 30s is not a very popular view of science anymore. There may still be people around who agree with some points, but overall, Logical Positivism is considered a somewhat outdated view. Especially the verifiability criterion is problematic. Karl Popper’s principle of falsification, the disproving of theories, is now the leading principle in the philosophy of science. People who therefore continually demand positive scientific proofs are over 80 years outdated. they shouldn’t be saying “can you prove this?”, rather they should be saying “can you falsify this?”.

But then again, maybe all of this philosophy of science talk is also pretty meaningless. Before I get carried away too far – I found a nice quote which should pull me back to the solid ground of reality:

“Philosophy of science is about as useful to scientists as ornithology is to birds.” Richard Feynman (1918-88)