Thursday, January 10, 2008

In pursuit of 'Rationality' ( A 'Probabilistic' Explanation)

"All the World's a stage and we all are actors" said William Shakespeare. When I read this poem way back in my 9th grade, my understanding of this was totally different as against my current interpretation. Most of us are not true to ourselves. We are not truely rational though we proclaim so. Why is it so?

A child is born with certain numerical abilities. Even before mathematics is formally taught to a child, it can count the number of toys it has with it. It can add the number of toffees it has even before the mother teaches 'addition'. The logical explanation for this characteristic is that the child has genetically inherited such a trait. Man has been playing around with mathematics for tens of thousands of years and hence he is genetically strong.

I have always loved mathematics till now and so have many of my friends. But I have observed one peculiar behavior. Most of my friends including me are pretty strong in Algebra, Geometry, Numbers but most of us are dreaded by the chapter 'Probability'. Most people I have observed are not very comfortable with 'Probability' and 'Combinatorics(Permutation and Combination)'. What can be the reason for this? The most common answer I get from people is that 'Probability' is tough. But why is it tough?

It is an intrigiung fact that though Geometry, Algebra, Numbers had been in use for thousands of years, 'Probability' is one branch of science which was popularised only post 15th century when some gamblers wanted to estimate their return from the game of chance. Probability is relatively the new kid on the block of science. So the element of 'Probability' is not strong in our genes. And it would still take hundreds of years before genetically, the mankind is comfortable with probability. But what is the implication ?

'Rationality' is strongly related to 'Probability theory'. One way of looking at rationality might be choosing the right path from a given set of alternatives. Such a choice can be termed as rational decision making. Decision theory was popularised by the 18th century mathematician Thomas Bayes (of Bayes' Theorem fame). 'Decision Theory' applications are indispensable tools for the rational decision making by managers(My MBA friends would agree with me on this fact). But we don't use decision theory beyond our professional life. Do we draw a decision tree for our day to day decisions? A lot of our decisions are taken not from our minds but from our hearts. We are not perfectly rational simply because we are not genetically coded so. Nevertheless we are in pursuit of rationality.

It will be a really interesting proposition when more and more of rationality creeps into the society. It'll be a whole new world. Marketers can't allure customers by 'Buy 1 get 1 free'! Investment Bankers and other traders would no longer successfully underwrite European Options! Insurance industry would rewrite its business equations (FYI Insurance Rationale is very much based on Bayesian Probability theory)! And students would say 'Probability' is a piece of cake!!

8 comments:

Anonymous said...

Interesting post, but I won't completely agree with the fact that rationality is linked to probability to the extent you are saying

Kartik Chandrasekharan said...

Raghu, You're right but my argument is NOT that Rationality is ONLY causal variable linked with probability, but 'Probability' is ONE OF THE MANY variables which has correlation with Rationality and in this post I have spoken about the 'Probability' factor

Sheks said...

I have studied Decision Theory in my UG and some deep thinking reveals it is possible to use DT to situations beyond professional life provided that situation involves numbers.For instance,last week I was caught in a situation of choosing between two brands of chyavanaprash.Both were popular brands that were endorsed by two famous Bollywood actors.There were other factors like price,weight,the amount you are carrying and ingredients(one of these claimed it had gold and silver as ingredients).I ultimately chose the one with gold and silver as ingredients.I did not realise,at the moment of buying,but now when I look back I realise I have applied decision theory.

Kartik Chandrasekharan said...

@Sheky: I know you are extremely good at number theory. The route to probability is number theory --> Combinatorics --> Probability. No doubt you are rational and use decision theory..!
:)

Unknown said...

Nice post. I never correlated the length of a particular field in existence to our genes...

Annamalai said...

Creation and application of theories and concepts around real world incidents go on to become the best of theories.. Some of John Nash's theories are good cases in point..

And after a tiring day in front of the comp for work after getting home while searching my eye glasses, so many times have I thought of Ctrl+F !!!

Kartik Chandrasekharan said...

@ Anna: Ctrl + F was a good one :-)

Anonymous said...


Hey guys great post.