Algorithms for kids

February 15, 2014

I recently gave a talk about algorithms to a 6-th grade class. My slides are below (an English version and a Hebrew version).

What I believe worked very well was going through the execution of the algorithms step-by-step and having the kids take turns at saying in advance, before I switch to the next slide, what the changes they are expecting see are – where the instruction pointer arrow will move, what variables will change their values and what new output will be emitted.

algorithms-engEnglish version

algorithms-hebHebrew version


About learning

February 3, 2014

I have spent my childhood and adolescence implicitly believing in ideas about learning that in later life I have come to disbelieve. It appears to me that those ideas are quite common in our society, including among schoolchildren. These false ideas cause significant harm to many of those who believe in them and, being widespread, to society. I therefore think it is important to disabuse students, and particularly children, of these ideas.

The false ideas about learning maintain their hold in the mind of the public mainly because they are rarely examined. One of the false ideas is that the nature of learning is self-evident and needs no examination. This, of course, makes those ideas self-reinforcing.

This essay is a brief description of those erroneous ideas about learning and of an alternative view – in my opinion, the correct view. To make things concrete, I start by listing a set of practical implications of the rejection of the false notions and adoption of the alternative view. These are things that can and should be done by the various people involved in education – students, teachers, and managers of education systems.

Whatever Marx and Engels may have thought about the future of the state, the real question is not whether a public power will be needed in a classless society, but whether that public power will constitute a problem. In other words, are there certain problems inherent in public power itself whether or not it is class power? I take it for granted that it is hopelessly naive to believe in an advanced socialist society administered by simple forms of direct and spontaneous democracy. It is difficult to avoid the conviction that even classless society will require some form of representation, and hence authority and even subordination of some people to others. That premise granted, it must be added that, whether or not one uses the term “state” to describe political and administrative power in a classless society, it seems unduly optimistic to believe that there can ever be a case in which power exercised by some people on behalf of others does not constitute a problem. Socialist political theory must, therefore, face the problems posed by representation, authority, and subordination, and the fact that their very existence makes possible the misappropriation of power.

Ellen Meiksins Wood

Free Will

April 12, 2012

I recently came across a site with some promise – Radical Philosophy magazine. The current issue has an interview with Noam Chomsky discussing, among other things, Free Will. I found that I do not agree, and to some extent do not understand, his position. This serves as an excuse to present my theory of Free Will.

I will grant at the outset that I am not well read on the subject. I have never read, for example, Descartes’s theories on this issue. My theory is very simple, but, I think, is quite serviceable in dealing with the limited issue of Free Will. It does not address the matter of consciousness, which I think is more complex.

My understanding is that:

Free Will is that part of a decision making process or action generation process that is inexplicable to the observer.

Read the rest of this entry »

I wrote the post below a while ago – not long after my original Fermi’s paradox post linked to. Somewhat startled and uncertain about the conclusions drawn at the second part of the post, I filed it away. Looking at it again, the reasoning seems plausible, and no obvious counterarguments come to mind.

This post aims at pursuing somewhat further a line of thought explicated earlier. As before, the jumping point is the realization that among all [near] space-faring civilizations (SFCs) to ever develop in the universe (in the past or in the future) the human SFC is a-priori unlikely to be an a-typically early one. Thus, either (1) there are, and ever will be, very few SFCs in the universe (and of those, all those that are earlier than humans either met with misfortune or have shown self-restraint in polluting the universe) – this is the “rarity” option, or (2) there are many of them, but they – in some coordinated way – are making sure we are unable to observe them – this is the “protected wilderness” option.

The first possibility – rarity – which has some proponents – can be developed further: sub-possibility (1a) is that the universe is naturally inhospitable to SFCs – in the lifetime of the universe there are likely not to be many SFCs. Sub-possibility (1b) is that it is the first SFC that achieves cosmic scale (presumably the human one) manages, deliberately or non-deliberately, to suppress all later budding SFCs.

Under both those options, the universe as we know it – the pristine, unkept place which gave birth to the human SFC – cannot exist for much longer (i.e., more than, say, a few hundred times its current age), since if it did, some later SFCs would develop, some of which, presumably, would have cosmic-scale impact.

The same type of appeal to non-extremity, however, can also be used to argue that we, i.e., people living now, are not particularly early specimens of the members of the human SFC. Thus, the total number of human beings being part of the human SFC is unlikely to be much larger than a few hundred times its current and past membership (which is about 10 billion people). This seems to rule out the possibility of a large scale colonization of space by humans, but does not rule out over-running of the galaxy (or universe) by von Neumann probes originated by a human-made seed, which could be a cause for the non-development of other civilizations.

Newcomb’s paradox

January 6, 2010

This post presents my analysis of Newcomb’s paradox. I have written it back in 2001, after having found the paradox discussed in Martin Gardner’s book “Knotted doughnuts”. Reading the discussion in the Wikipedia entry, I find my resolution more satisfying than those offered there. While I clearly take the “no free will” avenue which is mentioned in the entry, I think that drawing the analogy to a program-programmer situation reveals the essence of the situation, and avoids unnecessary muddles such as references to “reverse causation”. It is also worth noting that determinism is also not a necessary factor in the setup. Even if the computer could use a random number generator that is not predictable by the programmer, the situation would not change materially.

Newcomb’s paradox:

A psychologist comes to you claiming to have invented a machine able to scan your brain and predict with certainty your future actions. She proves her machine’s ability by predicting numbers you choose and all other kinds of actions, until you are convinced that the machine really works. In many trials you have never seen it fail.

She then puts a $10 bill on the table, and gives you a sealed envelope. The envelope and its contents are yours. You are also allowed to take the bill if you want to. She says that she used the machine to predict whether you will take the bill. The envelope is empty if the machine said you will take the bill, and it contains a hundred dollars if the machine said you will not keep the bill.

The problem is: should you or shouldn’t you take the bill?

Argument against taking the bill: If you take the bill, the machine would have said you will, and therefore the envelope would be empty, meaning you will total $10. If you do not take the bill the machine would have known that too, and the envelope would contain $100. Therefore not taking the bill yields higher return.

Argument for taking the bill: Say there are x dollars in the envelope. If you take the bill you get x + 10. If you don’t, you get x. Therefore taking the bill yields higher return.

My analysis:

Read the rest of this entry »

Where are they?

November 21, 2007

Fermi’s paradox can be reasonably resolved in only two ways:

  1. Technological civilization is a nearly unique occurence. That is, very few technological civilizations (such as that of humans on present-day earth) have ever developed in the observable universe, or,
  2. There exists a space faring civilization that maintains our galaxy, or at least our area of the galaxy, in a pristine state.

If both 1. and 2. are false, then there would very likely arise at least one civilization that would create self-duplicating probes around the universe. Unless some entity was cleaning these probes out of our [area of the] galaxy, such probes would be ubiquitous and evident from (or even on) earth.

The paradox therefore implies that either

  1. Our existence is a miracle on a universal scale, or
  2. There exists a powerful body that has specific objectives and it manipulates our of space in order to further those objectives.

Either of these options takes us some significant step toward a theistic position.

Update: Some discussion at “Daylight Atheism“. It turns out those self-duplicating probes are called von Neumann probes.