July 25, 2021

The world is not a logical place

by Neil Rickert

Let’s start with some definitions:

  • logical: in accordance with the laws of logic;
  • illogical: contrary to the laws of logic;
  • alogical: the laws of logic are not applicable.

My title is suggesting the last of those — that the laws of logic are not applicable to the world.

Of course, we do use logic. But we have to do some preparatory work to make it possible to use logic.

A logical world is a world of immutable objects. I’ll refer to those as “logical objects”. When doing mathematics, the numbers are examples of logical objects. In logic, we use the idea of “identity”, where A and B are identical if those are really just different names for the same logical object. So 3+1 is identical to 2+2, because those are both ways of referring to the same number 4.

In the world we live in, there are no immutable objects — see my earlier post about change. And what we mean by “identity” and “identical” can sometimes be confusing. Those are because our world isn’t really a logical world.


How do we deal with this situation? We categorize. That is to say, we divide the world up into parts (i.e. categories), and treat those categories as if they were logical objects.

Some people think of categories as collections of individual objects. I prefer to think of categories as arising from carving up the world into parts. What we think of as individual objects are themselves categories. We think of a person as an individual. But a person changes. The atoms which constitute that person today will soon be gone, and replaced by different atoms. A person’s appearance changes due maturing and aging processes. But we see these variations as the same person, because when we carve the world up into categories we place the variations of that person into the same category.

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July 19, 2021

Mental confusion

by Neil Rickert

I decided to have a little fun with the title, so it might be a tad misleading.


There is a thesis going by the name “mentalism” which is common in philosophy of mind. And there are things about mentalism that I find puzzling. So that’s the topic for today’s post. In his book “Psychological Explanation”, Jerry Fodor defines “mentalism” as the rejection of behaviorism. A large part of his book is engaged in criticizing Gilbert Ryle’s “The concept of mind”.

A side note. I looked up Fodor’s book in preparation for writing this. Amazon lists it as a paperback for $1500. Wow! I read it some time ago, borrowing from the university library. It is surely not worth $1500. (Amazon does also list less expensive used copies).

For myself, I guess I am really a behaviorist. And that may be why I find mentalism to be puzzling.

I take the term “mental” as having to do with the mind. So thinking would count as a mental activity. But it gets more complicated,, because some people talk about unconscious thinking. I doubt that there is any such thing.


I already have problems with the word “belief”. The verb “to believe” is straightforward. No doubt there are many statements that I would believe. But I never sure what is a belief. The noun “belief” used as an abstraction to refer to the concept of believing seems unproblematic. But that is not how “belief” is used.

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July 11, 2021

Against semantic externalism

by Neil Rickert

Sometime, I think it was back in the 1990s, I was involved in an online discussion of AI. I casually remarked that meanings are subjective. To my surprise, somebody gave me an argument against that. The basic idea was that language is shared in the community, and therefore meanings must be shared, so could not be subjective.

I remained unpersuaded, so I was pointed to Hilary Putnam’s paper “The meaning of ‘meaning'”, where Putnam argues that “meaning is not in the head.”

This post is about why I disagree. The expression “semantic externalism” is commonly used for the view expressed by Putnam and others, that meaning comes from the community rather than from the individual person.


My own experience suggests that people disagree a lot about meanings. They perhaps believe that they are disagreeing about logic or about evidence, but often the real disagreement is about meanings. That’s where I get the idea that meanings are subjective. As an example, look at arguments about “free will”, where disagreements over whether we have free will often look more like disagreements over what we mean by “free will”.

Of course, it is quite possible — and even likely — that what I mean by “meaning” is not the same as what Putnam means by “meaning”. But, if that is the case, then our own disagreement about the meaning of “meaning” is evidence that meaning is subjective.

Twin Earth

In his argument, Putnam introduces the idea of “Twin Earth”. Here, Twin Earth is a planet much like earth, with similar people. And what’s in the heads of Twin Earthians is said to be the same as what’s in the heads of us earth people. But, on Twin Earth, the liquid that they call “water” actually has a chemical composition of XYZ instead of H_2O. Yet the Twin Earthians talk about it as “water” much as we would for H_2O.

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July 5, 2021


by Neil Rickert

sThere’s an old saying: “The more things change, the more they remain the same.” But it seems to me that you could also say “the more things stay the same, the more they change.” Or, as people sometimes say, “We are in a world where the only fixture is that everything is changing.”

We live in a world of change. And that’s the idea behind this post.

In the beginning

According to Genesis, it all began with the creation of the earth as a solid foundation. But, since then, Copernicus, Galileo and others have persuaded us that the earth is actually adrift, moving around the sun. Later astronomers found that the sun itself is adrift, going around the Milky Way galaxy. And the Milky Way galaxy, much like millions of other galaxies, are adrift in the cosmos.

Once we understand it, this is not particularly surprising. If you set a boat in the ocean, you expect the boat to drive with the tides, currents and winds. You can stop the drift by anchoring the boat to the continental shelf. But then we have learned that the continents are themselves drifting.

It seems that everything is adrift, and nothing is fixed.


If we look to science, we see an attempt to give us stable measurements. For example the Newtonians fixed time based on the rotation of the earth, and they fixed length based on a fixed platinum rod in Paris. But these are all somewhat arbitrary choices.

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June 28, 2021

Musings about logic

by Neil Rickert

Logic has always come naturally to me. Perhaps that is why I went into mathematics. However, some people find logic to be quite difficult. Even some very creative people can have difficulty with logic. I guess it is just as well that we are all different and can benefit from that diversity.

For me, as a mathematician, the term “logic” is used for inference involving the strict following of rules. However, people seem to have varied ideas about logic. So this post will be a somewhat rambling stream of comments (musings).


It is sometimes said that if the only tool you have is a hammer, then before long every problem begins to look like a nail. And if the only tool you have is logic, then every problem begins to look like a proposition.

Logic is not the only tool that philosophers use. But, in my opinion, they do seem to give it too much emphasis. And, perhaps as a result, they do tend to put too much emphasis on propositions. We see this when they define knowledge as “justified true belief”, so as to have a propositional account of knowledge. But it has always seemed wrong to me. As I see it, the knowledge of a plumber is in his ability to fix the pipes; he does not need to give eloquent speeches about pipes.

Similarly, philosophers of science often describe scientific theories as belief systems. But this, too, seems wrong. A theory is much more a system of research behaviors than a system of beliefs.

Mr Spock

In the Star Trek series, Mr Spock was notable because he did everything with logic and avoided emotion. But here’s my question: if there was no emotion, why would he even care whether he got to logic right?

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June 21, 2021


by Neil Rickert

I skipped posting last week. I had planned to post about knowledge and belief, but decided to skip that post.

Conventionalism is interesting, in part because much of our life seems to depend on social conventions. And, in part, because philosophers seem to be strongly opposed.

According to Wikipedia, “Conventionalism is the philosophical attitude that fundamental principles of a certain kind are grounded on (explicit or implicit) agreements in society, rather than on external reality.”


It is usually agreed that a social convention is an agreement, perhaps implicit rather than explicit.

The rule that we should drive on the right side of road is often mentioned as an example of a convention. In some parts of the world, including Australia (where I grew up), people instead drive on the left side of the road. That there was a choice between driving on the left, or driving on the right, illustrates why conventions are said to depend on arbitrary choices. But those two choices (left vs. right) are not the only options. For example, there could be a system where people drive on the left on even numbered days and on the right on odd numbered days. This would be more confusing, with probably more accidents. But it serves to illustrate that there is often a degree of pragmatism in our choice of convention. Saying that a convention is an arbitrary choice does not rule out the involvement of pragmatism in the making of that choice.

Poincare proposed conventionalism for geometry. In his view, the axioms of geometry derive from our measuring conventions. I agree with Poincare on that.

Hilary Putnam argued against conventionalism in “The Refutation of Conventionalism”. One of his arguments was that under conventionalism there could be no matters of fact. I just measured the height of my desk as 74 cm. That’s a matter of fact which depends on the measuring conventions which define the centimeter. From the way that I look at it, all facts are relative to the conventions that we follow when observing those facts.

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June 7, 2021

Notes on consciousness

by Neil Rickert

In this post I will comment on the direction of my ideas about consciousness. However, it will not provide the reductionist account that some people seem to want.

The hard problem

David Chalmers divided the question of consciousness into what he called “the easy problem” and what he called “the hard problem.” Personally, I think the easy problem is actually quite hard. But I’ll discuss that later in this post. And I am inclined to doubt that the hard problem actually makes sense.

For Chalmers, the easy problem is the problem of getting information about the world or about our immediate environment. The hard problem is that of explaining conscious experience.


The hard problem is usually defined in terms of qualia. Here, “qualia” is a plural term that is said to refer to the qualities of our conscious experience. The corresponding singular term is “quale”.

I don’t much care for qualia talk. While I have a rough idea on what people want to discuss, it is always limited to a vague idea. There is nothing that I can pinpoint that I would call a “quale”. So I am not convinced that the qualia words actually refer.

I guess that makes me a qualiaphobe. That’s the term used to describe people who do not like qualia talk. It seems to me that qualia talk encourages us to see everything about conscious experience as objective, when it is really subjective.

Yes, I have conscious experience, as I assume others do. But I have only experience of my own conscious experience. I have not experienced that of anyone else. We can talk about our conscious experience because we share a language. But we do not share the experience itself. For all I know, the way that I experience red might be similar to the way that you experience blue. Our ability to talk about that experience is not sufficient for us to actually settle such questions.

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May 31, 2021

Recent posts on “truth”

by Neil Rickert

Today I want to give an overview of what I have been pointing to in recent posts. That is to say, I want to put them in perspective.

Truth is important. If you think I have been arguing against the idea of truth, then you have misunderstood my intentions. When I read various arguments, I see many misconceptions about truth. I have been attempting to clear up those misconceptions.

Why and how?

I have been studying human cognition. And one of the things that we humans do, is make assessments of truth. In order to understand cognition, we need to understand how we make those decisions.

My approach has been to attempt understand human behavior in how we use “true”.

Truth is a human artifact

Perhaps the most common misconception is the idea that truth is human independent. We see this, for example, when people talk of “the way the world is” rather than “the way that we see the world” or “the way that the world is to us”. When they talk of “the way the world is,” they typically are talking of true statements that can be made about the world and they are taking it that this is human independent.

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May 24, 2021

Truth, information, science

by Neil Rickert

Philosophers of science tend to want to see scientific theories as true. I sometimes point out that Boyle’s law is false. Some time ago, I wrote an earlier post saying that Kepler’s laws are false. In this post, I want to paint a picture of where truth and information fit into science.

The stopped clock

You have probably heard the saying, “a stopped clock is right twice per day”. And, along the same lines, we can say that a clock which is 1 minute slow is always wrong. However, you would probably prefer to have a clock that is 1 minute slow, than to have a stopped clock.

“Right” and “wrong” here are references to truth. The example of the stopped clock suggests that there is more to science than truth.

We can, instead, look at it in terms of information. The clock that is 1 minute slow is actually giving pretty good information about time. It isn’t perfect information, but it is good enough to be useful for many purposes. The stopped clock, by contrast, does not provide any useful information. Yes, twice per day it has the correct information. But that stopped clock cannot tell us whether this happens to be the time of day when it is correct. Since it does not tell us that, we cannot trust the time as reported by the stopped clock. It is, at best, useless information.

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May 17, 2021

Truth and correspondence

by Neil Rickert

The title is a reference to the correspondence theory of truth. This is not a post about letter writing.

When asked what they mean by “true” people often mention the correspondence theory. However, I find the common descriptions of the correspondence theory to be unsatisfactory. So this post will be an attempt to make sense of the idea of correspondence.

The correspondence theory is sometime said to say that a sentence is true if it corresponds to the facts. I always saw this as puzzling, because to me the term “fact” was just another name for a true statement. Described that way, the correspondence theory of truth seemed to just say that true statements are true and false statements are false. Of course, I did not disagree with that, except that it did not say anything at all.

It is sometimes suggested that facts are metaphysical things, and that correspondence to facts means correspondence to these metaphysical entities. I have trouble trying to understand what a metaphysical fact might be. Several hundred years ago, it would have been taken to be a metaphysical fact that the earth is fixed and the sun goes around the earth. Today, we instead say that the earth goes around the the sun.

Another way of presenting it, that I sometime see, is to say that a sentence is true if it expresses what is the case. But, once again, “what is the case” just seems to be another word for “true”, so we are again left with the correspondence theory saying that true statements are true and false statements are false.

Truth as a property of syntactic expression

There’s an intuitive idea, that a statement is true if it corresponds to reality. But it usually isn’t defined that way because of the difficulty of explaining “corresponds to reality”.

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