Words are important, after all, if you are engaged in a discussion then you will not get very far if the two of you mean something completely different by the same word. But unless you are a philologist then debates over words should never be the most important thing.

Science is about theories (explanations) and the evidence that tests those theories. Nevertheless, a lot of work in science goes into classification – defining the meanings of words for classes of things. Think of the taxonomy of living things, geological strata, the Periodic Table. These are important and many people put a lot of work into these things. But it is done only to support the real business of science – creating and testing theories.

Added – Popper wrote in All life is problem solving:

Of course, nothing hangs on the words ‘democracy’ and ‘tyranny’. If, for example, someone called unfree states ‘democracies’ and the constitution of the United Kingdom or Switzerland a ‘tyranny’, I would not get involved in a dispute over whether these terms were right or wrong. I would simply say ‘If I had to use your terminology, I would have to describe myself as an enemy of democracy and a friend of tyranny’. This allows one to avoid getting lost in terminological disputes; the important thing is not words but real values.

I don’t see how a theory could be ‘rational’ or ‘irrational’. It’s possible for a person to behave rationally, and therefore to adhere to a theory rationally.

It’s also possible for people to assent to the idea that a particular person is behaving (or adhering to a theory) rationally. Science makes that process as explicit as possible. But in general it’s impossible to know if a person is behaving rationally or not.

We can of course theorise about how people behave. For my money, the best theory of a large range of human behaviour is that people avoid cognitive dissonance. That is, they interpret or filter evidence to avoid clashing with an existing point of view or interest, because doing so avoids mental distress. (This seems to explain the behaviour of anthropogenic global warming denialists.)

This behaviour is, of course, the opposite of what critical rationalism regards as rational behaviour. But who is to say it’s not rational to the person rejecting the evidence? After all, if your main aim is to avoid pain (or to mislead other people into accepting something) rather than to discover the truth, then it may well be rational to behave in this way.

If your aim is to try to discover the truth about something, then CR says that the rational way of doing this is to cope with the evidence regardless of the pain it causes you.

It is possible to reason about these processes on a meta level too (to my mind ‘rational’ implies ‘reasoning’ implies ‘conscious’), and try to identify those parts of one’s mental processes that involve cognitive dissonance and consciously to override them. Any serious application of critical rationalism must involve this.

Richard Burnham

This is possible thanks to research in genetics and molecular biology that unveils the structure of organic compounds and life.

Once the evolution mechanism is unveil, prediction mechanism could be part of it to test future evolution of species.
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What do you mean by “incomplete”? All theories are incomplete in the sense that it is impossible to predict every possible state of affairs of a real system in the future even if they are fully determined by the theory. For example, the evolution of the solar system cannot be predicted indefinitely in the future, even though (omitting smaller effects such as interplanetary gas and dust and solar wind) there is no reason to suppose the state of the system is not determined by gravitational theory.

“Prediction” in the sense of testing a theory has nothing whatsoever to do with time. It is simply a statement of logical implication between a general, explanatory statement (theory) and a particular state of affairs that that theory implies could exist and could not exist if that theory were not true. The state of affairs could have existed in the past. Indeed, geological theories are tested against rock formations that mostly were formed long before man existed. Someone used “retrodiction” for this, but it is in fact a timeless logical relationship.

Theories are not testable in themselves. In order to test any part of a theory, you have to build a “model”. A model instantiates the theory with physical situations and particular values of parameters. It may be designed to isolate a particular implication of the theory for testing, such as the relationship between two variables. The kind of model that most people will find familiar is probably a physical model. If you have done physics labs you may remember such things as using springs to find the relationship between a force and the extension of the spring, or inclined planes to find the laws governing the acceleration of a body under gravity.

In the case of evolution, the model is a conceptual model. It consists of all the relationships that have been hypothesised between species, their fossils, the geological strata they are found in, their structural and DNA relationships and all the other relevant evidence currently available (including mathematical models of evolutionary processes). This model has been being built for over two centuries, and is much too big for any one person to hold in their head – it is spread through the scientific literature, some of it long forgotten or ignored.

Nevertheless, it renders the theory falsifiable because potentially somewhere in this model you could find relationships between the parts that are not compatible with the theory of evolution. Creationists are perfectly well aware of this and are always trying to interpret (and often fake) evidence to show that, for example, dinosaurs and humans are recorded in the same rock formations. (Suspicions should be aroused by the fact that they always find this evidence in spectacular and newsworthy species like humans and dinosaurs – you don’t find much creationist research on the scientific staples of E. coli and fruit flies, let alone obscure fossils. In fact, creationists tend to mock real research, vide Palin and McCain.)

Adding new evidence to this conceptual model supports, or corroborates the theory, but it does not amount to proof, because the theory remains potentially falsifiable. In fact, new evidence makes the theory potentially more falsifiable, as there are more relationships within the model that have to be true for the theory to be true.

Models, of course, have imperfections, which means that when a relationship does not fit you don’t immediately throw out the theory. Our physics experiments rarely fitted the textbook relationships, because of friction, air resistance, boredom and other factors. In advanced work you may have to use statistical techniques to study the relationship you want. In a conceptual model, there are always going to be problems over interpretation of the available evidence. As the theory is well-corroborated, people will review the interpretation of the evidence before rejecting the theory, and to an outsider this can look superficially like re-interpreting the data to fit a dogma, which is what creationists do.

In Arabic, numbers are written in the same system as in English (even though the symbols are different)- high digits on the left, low on the right. This is why we call our numerals in English “Arabic” numerals – as they came to us via Arabs from India. So, if there is an effect, it can’t be due to the way numbers are read.

(One thing though that has not occurred to me before. Do Arabic readers somehow “read” the numbers differently, given that interpreting the high digits first runs counter to the direction of the surrounding text? I taught science to Arab students for five years, so it’s a bit embarrassing that I never thought about this.)

However, I’m sceptical about the whole post, and agree with another comment about the lack of error bars. I think the “effect” needs further testing before time is wasted on explanations for it.

Despite what someone said, Popper did not appear to condone waffle. He did say that he did not believe in getting hung up over the meanings of words, and would happily agree a contrary (though undoubtedly temporary) meaning for a word if it would advance the discussion. What he preached (even if he did not practice it as thoroughly as might be expected) is that the participants in a discussion should in good faith attempt to understand each others’ meanings, as they both (presumably) expect to gain something from the discussion. One of the things you may need to do in the case of misunderstanding is to ensure that you are all using the key word(s) with the same meaning. This does not mean going back and defining all terms in an infinite regress.

I have observed over a long period that the discussions here seem often to fall short of that ideal. It must now be about a decade since I commented that the meaning of a piece of text may not only be in the individual words or sentences, but also in larger structures – in paragraphs, articles or even in whole books. So McD’s habit of atomising all texts before responding to them is not only destructive to their meaning, but actively militates against a useful discussion, and must make it just about impossible to learn anything from the other fellow you are debating with. And so it seems.

Another practice that is destructive to understanding is this nonsense about ‘worlds’ and ‘realities’. The reason for social interaction – and human conflict – is that we do all share the same world and the same reality, in the common, garden and obvious senses of those words. Using these terms in other ways seems calculated to bring about the state of affairs that is falsely claimed to be inevitable, that people or groups of people live shut out from all possibility of understanding each other.

Popper talked of ‘worlds’ 1, 2 and 3, but I hope that we all understand that this is a metaphor, and that these classifications are useful only in relation to how they help us understand our use of ideas in the real world, the one we all live in. One could raise a number of possible objections to this use of the word ‘world’. One might argue that it is meaningless. One might argue that it is not useful, that it fails to help others understand his meaning or causes unnecessary confusion (in view of what I have read in the past, I think this is a valid criticism, and I try to avoid it myself). Or one could argue that his metaphor is not true (that things and ideas just do not fall into classes in the way he claimed).

I am not, by the way, denying that some aspects of our reality are genuinely socially constructed. Marriage, for example, exists only as long as people recognise its existence and show a set of behaviours towards the married people that depends on the recognition of that construction (for example, turning up on a certain day and throwing confetti and toasting the newlyweds, inviting them out as a couple, and feeling rather differently about having sex with the husband or wife) . The same applies to governments (if everyone refused to recognise a government it would simply no longer be one) and the notion of ownership (as opposed to possession in the sense of control).

donalmcevoyuk wrote:
[snip]

Perhaps your intellect rises well above this assertion and you can show that the etymology of “cheers” is unrelated to the term “cheering”? (People say “cheers” when toasting; they are in effect “cheering” each other – its entry into the vernacular, as a surrogate for “regards”, is perhaps through this route (I am guessing); in which case etymologically it is related to “cheering”/toasting i.e. it’s a shorthand for “here’s to you”; of course, like “laters”, its overuse denudes it of almost any real meaning.

[snip]

The meaning of a word is what people conventionally use it to mean, not necessarily what its etymology implies. Otherwise we would all use the word “sad” in its ancient sense of “satisfied” or “satiated” (German “satt”).

Whatever the meaning of a sign-off or greeting (or toast) is, it’s something to do with the nature of human social interaction that seems to militate against abrupt beginnings and endings to periods of communication, and is possibly even less related to etymology than other words. If I say “goodbye” I am not invoking god, merely smoothing a separation in a formal relationship. If I say “bye”, “bye-bye” or “tschuess”, I am doing the same in a less formal one.

What DD actually means by “cheers”, of course, is for him only to say.