Archive for August, 2021

August 30, 2021

The importance of standards

by Neil Rickert

A long time ago, as a teenager, I spent time reading about science. One of the things that I noticed, was that the Newtonians put some effort into giving as a unified system of weights and measures. That is to say, they established standards for the measurements that scientists make, and the attempted to unify standards internationally.

That always seemed important to me. I took it to be part of how science works, especially so when we notice that measurement is very important to scientists.

When I look at books in the philosophy of science, I do not recall ever seeing the authors mention this standardization of measurement systems. Perhaps the philosophers of science do not see it as important.

Artificial intelligence

One of the things that AI researchers have been concerned about, is learning. And one of their theories of learning has been based on the physical symbol system hypothesis. The idea seems to be that the world is full of naturally occurring physical symbols, and an AI system can pick them up and compute with them. I don’t think there are any naturally occurring physical symbols. It seems to me that symbols are human constructs, and we depend on our own standards on how to use those symbols. So there’s that word “standards” again.

The idea, for that AI hypothesis, was that the symbols constitute information and an information processing system can use them as the basis for artificial intelligence. But I say “no information without standards.”

The problem

Imagine a young child who has learned the word “doggy”. As he walks away, a gust of wind rustles his hair. Oh, another doggy? If the child has no standard as to what constitutes a doggy, then he cannot tell that the gust of wind isn’t a doggy. In order to make sense of the world, we need to make distinctions. And we apply some kind of criteria when making those distinctions. How we apply our criteria are, in effect, our standards for perceiving the world.

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August 23, 2021


by Neil Rickert

People use the word “information” in a variety of ways, some of them mutually inconsistent. In this post, I shall describe how I prefer to use the term. My own usage is partly informed by my study of perception. And, of course, as a retired professor of computer science, my usage is partly informed by the use of information in technology.

The word “information” is used a lot in information technology. We talk about information being communicated or copied or transmitted. But we also think of newspapers as being sources of information. Likewise, human speech is normally considered to be information.

Shannon information

Claude Shannon is famous for his theory of information. He actually called it a theory of communication. People use the expression “Shannon information” in somewhat inconsistent ways. I shall try to stay close to what Shannon discussed.

Shannon was concerned with the question of transmitting information over a noisy channel, and with the problem of minimizing the errors that are due to noise in the channel. Shannon considered the use of both analog signals and digital signals. But the bulk of his work has to do with digital signals, and that will be my main emphasis in this discussion.

Shannon did much of his work at Bell Labs. And, of course, a major concern of Bell Labs was with telephone communication. These day, largely due to the work of Shannon and others, most telephone communication is done by encoding voice signals in a stream of binary digits. It turns out that this kind of digital communication can better deal with noise in the channel.

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August 16, 2021

About perception

by Neil Rickert

In a recent post, I suggested that perception is an important part of perception. One commenter disagreed, and wrote “Perception is simply raw sensory impressions”. That’s actually a common view. A lot of the literature on empiricism suggests that it starts with impressions.

I’m actually not quite sure what people mean by “impression” when they make such statements. I expect that they are probably thinking of conscious impressions — something that we can think about. However, it seems to me that much of perception is prior to conscious experience.

The expression “raw sensory impression” could also mean the forming of an image (in the visual case). I’m doubtful that we form images. I cannot see any good reason why an ability to form images would evolve, because it is hard to see much benefit from having such an ability. What really matters to an organism, is getting useful information about the immediate environment. So my own thinking about perception has tended to emphasize that information problem.


One of the problems for visual perception, is that we are moving. We move our bodies. We also move our heads relative to our bodies. And our eyes move (in saccades) relative to the position of our heads.

If you have ever tried taking a picture with a moving camera, you probably know that this can result in a blurry picture. A high shutter speed can reduce the problem. However, the response of retinal sensory cells is slower than high speed shutters, so that method is not available to the visual system.

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August 9, 2021

There are no foundations

by Neil Rickert

This post is, in part, a response to the post “In the first place …” on another blog. The author of that post writes:

It’s really strange having fallen from faith to now be starting to wonder if faith is the only way to underpin the very thing I used to push faith away with in the first place (rationality).

Here I am using “foundation” as the same as “underpinning”. So this post has to do with foundationalism in epistemology. To a first approximation, foundationalism is the idea that there is a starting set of assumptions from which all knowledge can be logically derived. And I guess that’s similar to the “presuppositional apologetics” which we see in religious circles.

Sam, the author of the post to which I am responding, goes on to write:

Does there have to be rational arguments for God? There are many rational people that believe in God. If we assume anyone who believes in God is irrational and has no root cause of belief, then we label all believers with the same brush. I’ve grown to hate this.

You can see Sam’s concern. From my point of view, there are no rational arguments for God. But that does not imply that believers are irrational.

To put this in perspective, consider the concept of mass from physics. It is a rather central concept. Yet there are no rational arguments for mass — depending, of course, on what you mean by “rational”.

I sometimes toy with the idea of writing a post “Logic is illogical; rationality is irrational.” The problem here is that both words (“logic” and “rational”) can have different meanings, and those different meanings can be in conflict. For example “logic” can be used to refer to a formal method of deductive inference. As a mathematician, that’s my preferred meaning for the term. But “logic” can also refer to using ordinary good sense in making decisions, and quite often ordinary good sense does not involve any formal inference.

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August 2, 2021


by Neil Rickert

I decided to take a break from my usual fare, and post something a little different.

These days, people are concerned about climate change. So there is a move toward using electric passenger cars. Thinking back to my youth, I remembered that most of our travel at that time was electric. And we did not have to worry about lithium batteries spontaneously bursting into flame.


Yes, that’s right. We mostly traveled by electric tram.

I grew up in South Perth, a suburb of Perth (Western Australia). And trams were how most people traveled, at least for local travel. It was actually quite convenient. Our house was perhaps 400 ft from a tram stop. We could quickly go downtown (i.e. to the city of Perth). And we did not need to hunt for a parking space. And I’m pretty sure that the typical carbon footprint was far smaller than what is typical today.

This was actually good for me in learning how to be independent. At around age 8, I was recruited into the choir at St George’s Cathedral (part of the Church of England in the city). So I was taking the tram to the city twice per week. One trip was for the rehearsal, and the other for the Sunday performance. I didn’t mind singing, and I got to ignore those boring sermons because it was only the singing that mattered.

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