Certainty and Knowledge

Elliot Temple
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Which categories did Popper agree with Kant on? Do you think Popper believed in the types of categories I described?

I think practically every philosopher we would call “a priori thinkers” tries to prove that some knowledge is a priori valid, as in guaranteed to be true. It would be contrary to Popper’s fallibilism to claim anything as guaranteed to be true.

So it seems you think Popper believes in inborn ideas like something akin to Plato? C&R:

The theory of inborn ideas is absurd, I think; but every organism has inborn reactions or responses; and among them, responses adapted to impending events. These responses we may describe as ‘expectations’ without implying that these ‘expectations’ are conscious. The new-born baby ‘expects’, in this sense, to be fed (and, one could even argue, to be protected and loved). In view of the close relation between expectation and knowledge we may even speak in quite a reasonable sense of ‘inborn knowledge’. This ‘knowledge’ is not, however, valid a priori; an inborn expectation, no matter how strong and specific, may be mistaken. (The newborn child may be abandoned, and starve.)

Thus we are born with expectations; with ‘knowledge’ which, although not valid a priori, is psychologically or genetically a priori, i.e. prior to all observational experience. One of the most important of these expectations is the expectation of finding a regularity. It is connected with an inborn propensity to look out for regularities, or with a need to find regularities, as we may see from the pleasure of the child who satisfies this need.

I don’t think Math knowledge would not be among the expectations that Popper hesitates to call “knowledge”.

I don’t know if Popper thought this would be knowledge of the mind or just instinct like animals have.

In LScD Popper implies he is against “apriorism”:

In short, like every other form of inductive logic, the logic of probable inference, or ‘probability logic’, leads either to an infinite regress, or to the doctrine of apriorism.

I don’t really want to just dismiss the Weyl quote, but I think it’s hard to interpret correctly, so a more clearcut example of Popper arguing for a priori could save me effort trying to understand this quote.

I tried searching Popper books for “laden” and some other keywords, but I couldn’t find any chapters on observation before theory or “theory laden observation”. If someone knows about chapters that discuss this I would like to read them.

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Observation plays an important role in science. Theories that contradict observation are rejected because reality is objective. It’s important to note that it’s our idea of what the observation is that criticizes our proposed theory. We can also criticize the idea of what the observation is, for example by saying there was an error in the instrument we used to measure the phenomena to get our observation. This does not mean that the observation was corrupted or that reality is non-objective or deceitful. Whatever observation you get from reality is what it is and is possible to understand correctly. But our idea of what the observation is is an interpretation of that observation.

(I think the paragraph below is quite complex, abstract and confusing, so maybe not the best to discuss)
Here observation plays a role in the growth of knowledge. We can say in a sense that observation plays a part in the creation of knowledge, because refuting some ideas lets us know the other ideas could be true. But if we are talking about the actual creation of the idea itself that is knowledge, then I think observation plays no role in that. The idea is created in our mind by our intelligence. The idea may have been influenced by ideas we have about observations, but I don’t think the observations themselves creates ideas. It seems to me that empiricism and induction suggests that (repeated) observation somehow creates ideas or makes the correct idea obvious. I don’t know exactly how the mind creates ideas, but I don’t think observations themselves, i.e. not ideas/interpretations of observations, creates knowledge.

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A priori in the sense that I am using it means before experience. I believe that you must start with observation before a conjecture would be made. If conjecture is the starting point then this presupposes something to base the conjecture on. And if it is not based on observation then it must be some sort of a priori knowledge. This is also a response to your

question.

I agree that the quote is hard to interpret. But what is not hard to interpret (and which was the point in me selecting it) is that Popper explicitly accepts some a priori knowledge.

How can you know what a table is without first observing tables?

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I think a priori should mean independent of experience, not merely before experience.

Do you recognize that Popper was very different from a priori thinkers like Descartes and Plato? Intellectualists usually start from some axioms they consider self-evident truths and want to build all of knowledge deductively upon this foundation. This isn’t at all like Popper.

I don’t think the definition of a priori matters too much here. The important thing is that you shouldn’t conflate Popper with intellectualists like Descartes, Spinoza, Leibniz or even Plato. It would be rationalist word substituting to say Popper and the intellectualists were all a priori thinkers, under your “a priori” definition, and therefore they’re very similar.

Given my extensive quotation, do you agree that Popper didn’t think of himself as a “rationalist” as in Cartesian intellectualism, but rather thought of himself as pro-reason?

If it is the starting point then it isn’t based on something, as a matter of logic. Are you saying something else?

I guess we can say it presupposes that the mind can create ideas. Which I do presuppose. I don’t think anyone knows how the mind creates ideas. People may know some things, but not in full detail.

When I say theory comes before observation, I don’t mean the ideas came before a human has made any observation. I’m saying that you don’t have to observe light from a faraway star bending around the sun to have the idea that the light will bend around the sun. You don’t have to observe the phenomenon to conjecture about the phenomenon.

How was the table invented? How could the inventor have the idea of a table before it existed? It’s the same as “How did the inventor of the plane know what a plan was before he created it?”. The answer is they conjectured it. The mind created the idea without having observed them.

For the table it’s possible the human first saw something table like in nature and then created another himself. But you cannot say the same thing about planes. Being inspired by birds isn’t the same as observing a plane. Computers were definitely not observed before someone had an idea of them.

How do scientists make hypotheses on phenomena they’re yet to observe through experimental tests?

Le Verrier predicted Neptunes existence using theory. So he knew about Neptune without having observed it.

Any human in modern times will have observed a table before they have an idea of what a table is. It greatly helps to make observations of things to figure out what they are.

Do you consider yourself an empiricist? If not, why not?

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I think in order to classify something you’re seeing as a being table, you have to first have a concept of what tables are. Because when seeing something, what you’re seeing isn’t obvious. Like how for ~all history we looked at the stars and didn’t know that stars are spheres of burning hydrogen gas. You have to first ask: what is this I’m seeing? is it a bed? is it a chair? is it a table? Being able to ask those questions means you have those concepts already. If you don’t have the concept of a table already, you will never identify what you’re looking at until you first create the concept of a table in your mind.

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Yes.

If conjectures happen without observation it would be synonymous to say that they happen either independent of or before experience.

I’m saying that conjecture cannot exist without having something to conjecture about. Just like consciousness cannot exist without there being something to be conscious of.

The mind creates ideas by abstracting from sense-data and forming concepts through induction. Does this provide full detail? No. Does it provide the general, necessary process? Yes.

The base is always reality. And observing reality is always the starting point. It makes no sense to start midstream and say that a new theory comes before observation. It is always observation that gives us the material to conjecture about.

By observing the facts of reality and abstracting to form a new generalization from particular facts already observed. You could also say by reorganizing that particulars into a new form. And just because the first inventor invented the table does not mean he had a concept of what a table is. He knew his particular thing but for there to be a concept you need at least two units that share the same essential characteristics before you can have a concept. So the concept of tables came from observing tables, not by creating the first one.

To make higher level abstractions like this you need lots of sense-data and lots of integration of that sense-data and a bit of creativity. You can’t start with the creativity, you need to start with observation of reality.

I would say I’m 60% empiricist and 40% rationalist. You definitely need an integration of both. Pure empiricism leads to materialism, which neglects our concepts, volition and reason. Pure rationalism leads to idealism, which is mystical, unknown and unverifiable.

Concepts are formed by abstracting observed similarities between two or more units and only then can you claim to have a concept.

Before you can ask what you are seeing, you must first see.

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(I agree, practically speaking).

These suggested to me that we were talking about different things when we say “before observation”. You seem to be talking about the base of human knowledge, and you take “before observation” to mean all theory came before any observation, so that would be inborn ideas. I’m speaking of whether you can have the idea of a thing before observing it, not about the base of all knowledge. My version doesn’t require inborn ideas. I’m not saying the idea has to come before the observation either, you’re more likely to observe a table before you have an idea of what a table is.

I find this absurd:

What is the functional difference between the knowledge of that particular thing and a concept? I’m not talking about how they were created. What’s the difference in content? The inventor of the plane could imagine different planes, from these he can draw out the essential characteristics. The inventor could imagine a wide range of applications and a wide range of possible measurements for the different characteristics. The inventor would have a concept of what it is that he invented.

You would have to hold that when he observed the second plane the idea the inventor had must radically change. I say he must have had largely the same idea before creating the second plane and after.

The same goes for computers and planes?

This is an example of knowing about something before observing that specific thing. Yes Le Verrier observed lots of different things which were valuable in predicting Neptunes existence, observations are invaluable for the growth of knowledge, but he did not observe Neptune itself. I’m not stating he had the necessary knowledge before he was born.

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But they logically can’t be formed like that. You logically can’t classify two observations as repeated instances of a pattern (i.e as being similar to each other) without first having an idea of what parts of the observed circumstances are and aren’t relevant. Because any two different observations contain infinite similarities and differences. You need an idea, a concept, a theory, of which differences or similarities between the observations do or don’t matter, before you can consider an observation to be similar to another.

What’s your point here?

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I came across this when reading The World of Parmenides, which comes after LScD:

This method is the method of conjectures and refutations; it is the method of taking many risks, by producing many (competing) hypotheses; of making many mistakes; and of trying to correct or eliminate some of these mistakes by a critical discussion of the competing hypotheses. I believe that this is the method of the natural sciences, including cosmology, and I think that it can be applied also to philosophical problems; yet I once believed that arithmetic was different, and that it could have ‘foundations’.

I think that settles it.