Reading various philosophers introduces to ideas we never think of. I came across Foucault and his take on power, punishment fascinated me. So, to understand his ideas I picked up A Very Short Introduction by Gary Gutting.

Some of the ideas/quotes which the author covers

1) Foucault said “The main interest in life and work is to become someone else that you were not in the beginning.”

2) What is an author? Is a person who writes shopping list on a paper an author?

3) Politics – distinction between polemics and problematizations. Gary writes “Political discussions should be driven by the concrete problems that raise our questions, not by the established theories that claim to be able to answer them.”

4) Archaeology of knowledge – every author writes under constraints of his time. Gary writes “But Foucault’s idea is that every mode of thinking involves implicit rules that materially restrict the range of thought. We will not be so much interested in, say Hume or Darwin as in what made Hume or Darwin possible.”

— marginalization of the subject
— do not ask what Descartes mean but “they use what Descartes – wrote as clues to the general structure of the system in which they thought and wrote.”

5) There is an intimate tie between knowledge and power. “Foucault claims that power has a positive epistemic role, not only constraining or eliminating knowledge but also producing it.”

6) Crime and Punishment – “The most striking thesis of Discipline and Punish is that the disciplinary techniques introduced for criminals become the model for other modern sites of control ( schools, hospitals, etc.). so that prison discipline pervades all of modern society.”

— Foucault says that modern approach to discipline produces ‘docile bodies’ through 3 means – Hierarchical observation, normalizing judgement and examination.
— “Society itself appears as a multitude of dominated others: not only criminals but also students, patients…. Each of us is the subject of modern power.”

Fears of homeschooling

Some of the fears which parents usually have –

1. Socialising
2. What if the child needs to rejoin the mainstream school (for whatever reason)?
3. What about the college admissions?
4. How to respond to those who keep pestering why home schooling?
5. Role of parents – if not capable to teach even though have knowledge or capable to teach but lack of knowledge in some subjects
6. Choose a curriculum or just explore different subjects

The NULL conundrum

So, you have a text field, named ‘Contact_Person’ defined in a table. This field is not required, and you allow null. Why not define a default value as empty string? It seems to me using an empty string is convenient. I don’t have to check for ‘null’ in the client application.

What is NULL? According to this wikipedia page,

The original intent of NULL in SQL was to represent missing data in a database, i.e. the assumption that an actual value exists, but that the value is not currently recorded in the database

Now, NULL represents UNKNOWN.

Sql actually uses three-valued logic. This article gives some examples, and writes

Accepts TRUE = Reject both FALSE and UNKNOWN
Rejects FALSE = Accepts both TRUE and UNKNOWN

On stackexchange, the argument made is logical that

I would say that NULL is the correct choice for "no email address". There are many "invalid" email addresses, and '' (empty string) is just one. For example "foo" is not a valid email address, "a@b@c" is not valid and so on. So just because '' is not a valid email address is no reason to use it as the "no email address" value

Few more interesting questions -


NULL is a textual representation of an unknown value. If you have two unknown values, you can’t conclusively state anything about their equality

Since it’s December, let’s use a seasonal example. I have two presents under the tree. Now, you tell me if I got two of the same thing or not.

They can be different or they can be equal, you don’t know until one open both presents. Who knows? You invited two people that don’t know each other and both have done to you the same gift – rare, but not impossible §.

So the question: are these two UNKNOWN presents the same (equal, =)? The correct answer is: UNKNOWN (i.e. NULL).

SQL does not any good forcing one to interpret the reflexive property of equality, which state that:

for any x, x = x §§ (in plain English: whatever the universe of discourse, a "thing" is always equal to itself).

Why does column = NULL return no rows ?

The most convincing argument for unschooling

Why should children be not sent to school and learn on their own at home? In, this article, the author says -

Unschoolers learn just like you or I learn as adults: based on what interests them, figuring out how to learn it on their own, changing as they change, using whatever resources and learning materials they find, driven by curiosity and practical application rather than because someone says it’s important.

In last 2-3 years, I have explored stuff which has interested me, on my own – whether it is history, philosophy, world music or maths. Even when it comes to programming, I learned most of the agile related stuff – due to intrinsic motivation of wanting to know how to do deliver working software in better and efficient way.


My first encounter with philosophy was Buddhism in 2003. I stumbled upon Buddhism through a book. But, at that time I did not know that philosophy was a field in itself. Recently, for some reason, I have become interested in philosophy. Actually, it was my interest in history which led me to reading “The Story of Philosophy”. And, then I joined the introduction course on philosophy at Coursera.
What is philosophy? According to professor in Coursera - Good philosophy is the activity of working out the right way of thinking about the things that matter most to us. What a wonderful definition! Don’t we face situations in life where we wish we could think through things and take an appropriate decision.The professor also says that philosophy is fundamental -

This is because philosophy involves stepping back and examining the presuppositions of what you’re doing, or the questions you’re asking. What are those presuppositions? Are they the right ones?

In a way, philosophy seems like scientific thinking :) Can we use philosophy to explore the IPL saga.

In last few weeks the betting scandal has rocked the IPL. Should IPL be banned? Why? Why IPL is so successful? Why people love watching T20? I prefer test match cricket anytime. Why do we watch sports? Should we go back to amateur era? Is any sport clean? Chess, my favorite game, is also facing crisis due to cheating by players using technology. So, is any sport completely clean? In fact, is any institution completely clean? Seems corruption is very much part of human organisations. The severity of corruption varies. To tackle corruption steps are taken. Some steps work, some don’t. So, IPL too has to take steps to clean the mess and carry on.

Philosophers ask various fundamental questions. Philosophy has some specific topics.

1) What is Knowledge? – Epistemology
2) What is morality? Is there a universal moral? – The Definition of Morality
3) Utilitarianism Utilitarianism is a theory in normative ethics holding that the proper course of action is the one that maximizes utility, specifically defined as maximizing happiness and reducing suffering
4) Most confusing is Metaphysics
5) Absurdism – From wikipedia, “In philosophy, “the Absurd” refers to the conflict between the human tendency to seek inherent value and meaning in life and the human inability to find any“. The ‘Myth of Sisyphus’ by Albert Camus is a famous work on absurdism. One can read the notes here –

I end with this quote by Socrates, as mentioned in, ‘The Story of Philosophy’,

Do you then be reasonable and do not mind whether the teachers of philosophy are are good or bad, but think of Philosophy herself. Try to examine her well and truly; and if she be evil, seek to turn away all men from her; but if she be what I believe she is, then follow her and serve her, and be of good cheer.

Educational Resources

List of resources which can be helpful for children education.

1. Jodo Gyan is an organisation working to find workable solutions to the problems in classroom practices
2. Vikram Sarabhai Community Science Centre
3. Arvind Gupta Toys
4. Navnirmiti is dedicated to acquiring, developing, innovating, producing and disseminating high quality, low cost/no cost (LCNC) learning methods, tools and systems to bring about universalisation of elementary mathematics and science skills and competencies
5. Alternative schools
6. Imagine a school where there is no curriculum

Interesting words used in ‘The wonder that was India’

I am currently reading The Wonder That was India. The book uses lot of words which I have not come across before -

1) Vassal (Feudatory) – A holder of land by feudal tenure on conditions of homage and allegiance. More on wikipedia

2) Suzerain – A sovereign or state having some control over another state that is internally autonomous

3) Primogeniture – is the right, by law or custom, of the firstborn to inherit the entire estate, to the exclusion of younger siblings

4) Desuetude – the state of being no longer used or practiced. In the book, relates to horse-sacrifice.

Multinomial Naïve Bayes

I am watching lectures on Natural Language Processing. In the week 3 lectures, professor talks about text classification. I found writing the formulas in words helps.

Given a training set, classify test set into a class

We need to calculate two probabilities
Say, we have a training set of 5 documents , with 3 documents of class ‘A’, and 2 documents of class ‘B’.

1) Probability of a class A, given a training set

= number of documents classified as ‘A’\total number of documents in training set

2) Probability of each word in the vocabulary

  • Vocabulary (V) – unique words in the training set
  • Assume there are 3 words in training set hello, world,goodbye
  • All documents for class ‘A’ are merged and same for class ‘B’
  • Probability of a word ‘hello’ given class ‘A’

    = number of times word ‘hello’ occurs in documents classified as ‘A’ + 1 \total words in documents classified as ‘A’ + V

Then, we tackle the test set. And, figure out which class is proportionally having maximum probability. How ?

1 ) Use the prior probability of a class, say ‘A’
2) And take each word in the test set, use the corresponding probability of the word in that class(‘A’) ^ frequency word in the test set
3) And, just multiply…