Mental model: rule of 72

I have been a fan of Charlie Munger's principle of keeping mental models, which will help one think properly and make prompt and correct decisions in most circumstances. I thought I should remind myself of the mental models I have been following, consciously or subconsciously, which suit my life very well.

Rule of 72 is one of them. The rule helps one to calculate how many years it will take for an amount of money to double at a given rate of interest. If the rate of interest is x% per year, then the money will double in (72 / x) years. For example, if rate is 9%, money will double in (72 / 9) = 8 years.

This rule also has a hidden rule in it, because it works only for compound interest - which means, one cannot take the interest out of the account at the end of each year. Thus discipline is required for the rule to work.

The math behind this rule is not complicated for the mathematically savvy. But the rule works whether you know how to derive this rule yourself or not! There are people who can do much more sophisticated math, yet fail to take advantage of the rule!

Facing Reality in India

Crimes against women have unfortunately become very common in India! Today my wife was so annoyed at the groping and molestation incident that happened in Bengaluru on new years day that she started discussing it with me with a lot of agitation. I didn't even look at the CCTV video that is available online when I read the news, because my watching the video isn't going to help the victim and is very well going to agitate me a lot. At my wife's behest, I eventually watched it and was quite shocked. I have to admit that I was disturbed for quite some time after watching it. Then my wife went to her own past and recalled how couple of men misbehaved with her in public transport several years ago in India. Then the discussion went to the Delhi gang rape case and how the victim subsequently died. Apparently the main accused is roaming free now after three years in jail, since he was a juvenile. At this point my patience on discussing world affairs came to an end. I hate thinking about problems which can be solved only by a miracle. And in a country like India, I have not seen any miracle happen in my life time (38 years). So the discussion with my wife ended abruptly with me not wanting to continue!

If you really start thinking about this problem at a personal level, all you can do is control things at your end. You cannot change other people or an entire country! No question that the perpetrators of such heinous crimes should be punished severely. But leaving that problem aside for a moment, my advice to women in India is to try and stay away from trouble as much as possible! It is unfortunate that your right as a human being is challenged, but you are living in a country with a lot of problems. You cannot change the country, but you can avoid putting yourself in precarious situations as much as possible. The way that girl was walking at 2:30 AM all alone by herself looked like she was going to get into trouble! Couldn't she have walked with a few friends? Couldn't she have not gone to a party that late at night? I am not saying such things cannot happen inside homes or be committed by close relatives, but at least you can try and protect yourself as much as you can!

Changing the country on this aspect will require a change at another level - law enforcement. When the police is weak and corrupt, crimes are inevitable. Even in a developed country, any rule that is not enforced is flouted. And any crime that goes unpunished encourages others to commit those crimes! I don't think most car drivers in developed countries would follow traffic rules if they are not strictly enforced or if the police start taking bribe! At least in the US, I believe people are afraid of the police for the right reasons and most people follow the rules most of the time. Yes, I don't want a cop to pull me over in the US, because that most likely means I have done something wrong - that is the only reason that should come to my mind. In India, when a cop pulls me over, I think how much this guy is going to take from me! In India we used to joke telling the only difference between a good thief and a bad cop is the police uniform; both of them take money from you! (The bad thieves hurt you physically too!) And a lot of cops in India are bad. The justification is that cops are paid so little that they need to "supplement" their incomes through bribes! When people start justifying mistakes, then there is no solution.

I remember my dad telling me during my last India trip about how bright the days after India got independence from the British. He was only 9 at that time, but he remembered how everyone respected Indian political leaders and how good the police force was, and how much everyone dreamt of having a great life! And he has seen India go from that golden age to its present stage in these 70 years!

I used to think a lot about how to fix the problems in India. After a few years I realized it was futile. I can only do things under my control, like following the rules, waiting my turn in a queue, pay taxes properly, try to stay away from trouble as much as possible and be honest; and if everyone just takes care of just himself, I think the country has some hope for fixing itself!