Randomized Thoughts

This is an imaginary love letter, written for an imaginary girl by an imaginative nerd.

Your presence makes every electron in the universe tingle,
Even the likes of inert gases will be ready to mingle.
You are more attractive than gravity of a black hole,
Any other guy who looks at you, should be labeled an a$$#@!e.
You are more vivid than picture in an HD television,
You generate enough heat to trigger a nuclear fusion.
You are more special than the special theory of relativity,
A touch of you causes any metal to adopt super conductivity.
A minute with you make me feel richer than Ambani,
Even a Tata Nano feels faster than a Lamborghini.

Your beauty might cause many accidents on the roads,
Coz you radiate brighter than light emitting diodes.
You catch people's attention like a Silk Smitha's poster,
With voice packed with energy of NASA's rocket booster.
In short, you are like a princess in a fairy tale,
With more curves than that of any sinusoidal wave.
I am feeling lucky that by you I am smitten by fate,
Your presence now is more universal than NAND-NOR gate.
You are better than any model in beau monde,
May our love stay stronger than an ionic bond.

I had a chance to go to Kolkata for a business trip. I will not subsitute Chennai as home for any other place, but found Kolkata surprisingly close to home. I had a pleasant stay for almost a full day, though divided into two halves (like a football game). Things that strike you immediately as you land in Kolkata is that, by mistake your plane landed in a bus stand. Kolkata airport is mighty small, though city dwellers take pride in it. The second most striking distinction of Kolkata is the ever red, ever lasting herbal art.

This herbal art is the combination of saliva, paan and some mystery material that makes the mix of the organic colloid distinctively red. Visitors can treat their eyes with delights of this art in every sq. meter of the city. Historically its argued that the art form is not a native art of Kolkata and was introduced by immigrants from Orissa. In either case, people of Kolkata have adopted and refined this delightful art for generations. The proof of this can be seen in the dry spits in a bus, tram, train, taxi, food path,.. (wait didn't I just say it is in every sq. meter of the city). I bet many fathers and sons of this joyful city would compare and contrast their respective artful spits lying side-by-side (but separated by a generation in time). If you are in Kolkata you just cannot miss this.

My friend took the visiting friends to Victoria memorial. Not sure why it is called memorial, but for memory I have taken a photo of me showing middle finger at some english-walla's statue there. It surprisingly felt the right thing to do then. Anyways, the police constable in Kolkata wear whites. My theory is that, there is so much red spit on the road, that people could easily mistake red light of the traffic signal for yet another paan spit. But red light's color cannot be changed, as across the world the traffic signals have to be uniform. So the intellectuals (I mean the people) of the city changed the uniform of the  police. Ingenious in my opinion.

Then there was a short ride on a Victoria Tonga. I was so happy when I sat on the tonga. We just crossed a traffic signal, and I was waiving my hand to the people who were waiting for green lights. I surpringly thought it was right to waive my middle finger at them, but realized that the tonga was not the horse of a Ferrari. So I chose to add the rest of the 4 fingers for my own safety. My Kolkata friend was embarassed by my theatricals and chose to duck his face under a cheap tourist hat we had brought earlier. Alas the joy of the tonga ride ended there. As soon as we crossed the traffic signal, we were disturbed by the honks of all the filty old buses of the local transport. Even though I could see the trams, my head was in a state of trauma. I wanted to travel in trams when I went to Kolkata, but Tonga and bus honks was enough to make my head spin.

My Kolkata friend took us to a place near river Hugli called Lover's point. Its filthy and dirty and has some weird looking statues. I don't know how that place could be Lover's point. There was nothing that was remotely romantic about that place. My theory was that this could have been Lover's point 50 years ago (when I think the place would have been much more cleaner and without those weird statues), but was surprised to know that couples come there even today. So my alternate theory took to the fact that there were boats that resembled the Gondola of Venice. So people in love can take a ride on it. But still.. all the boatman had no shirt and had huge pot bellies. And curtains of the boat cabin was substituted with lungis. I mean how can a guy or a girl can feel romantic in that setup? But I guess Kolkata and its people continued to surprise me. I find that many girls in streets of Kolkata were beautiful, but was scared of feeling romantic by now. Caution dear reader, if you have a significant other from Kolkata, next time you go to Kolkata do not feel romantic. Else you will be riding on a filthy boat with the breeze of a dirty river hitting your face through a lungi.

Next we went to Park Street. By this time I got into the usual lazy mode of Kolkata. Any more activities proposed by my friends was followed by Cholbe na, Cholbe na from me. But there was no Cholbe na when it came to lunch and we had our lunch in a delightful place filled with lovely girls (though this part of the trip was not planned). We had to board our flight soon and so before leaving I wanted to contribute to the herbal art form of the city. So we tried paan. I was chewing it for close to 5 minutes periodically checking with my friend if the paan + saliva colloid in my mouth was anywhere close to red. To my disappointment it seems there is some mystery material, that only people of Kolkata use, to make the paan red. Visitors like me cannot be shared with the precious secret and so I had to leave the city with no contribution made to its culture. But surely I have taken some of its culture in form of Rosagullas and Ghanti (that my friend's mom gave me) back home.

Thanks to Keshav Modi & family for such a wonderful time in THE CITY OF JOY. Thanks to Munish for paying for everything I enjoyed in the city (I have no intention of repaying him though).

Dear readers
Its been a long time since I blogged. Honestly I thought that the cardinality of the reader's set of my blog is zero. But it was brought to my notice by few of my friends that its been long time and they like the posts. So the number of readers of my blog ceased to be imaginary and have now become real. So dear reader, I am sorry that I thought you guys were 0+0i and not any X > 0 in number. Please accept my insincere apology for it and to make amends I have decided to waste few moments of my life every now and then for your benefit.

WARNING: Any person who thinks in the right direction (even left, up & down directions included) should not be influenced by randomized thoughts (just to remind its my blog's name). It is the sole discretion of the right, ---, --- & --- (please fill in the blanks) directional thinkers to continue thinking after reading posts of this blog. Any further damages caused to the neurons of your brain is strictly accidental (though intentional) and cannot be used as the evidence or cause to file a lawsuit on me. (You see I don't want to go to jail for your stupidity)

A lot is said about Women's bill to be discussed in the floor of parliament. The cartoonscape in The Hindu has saved me the trouble of describing the plight of this particular bill till today.

To be fair I am quite confused about this bill myself. Not because of the message and social uplift that this bill promises to bring about, but on the grounds of its implementation on basis of reservation. Its been said that 33% of the all legislature is to have women representation. That would mean that the all candidates of 33% constituencies should be women, and these reserved constituency will have to take turns. So one in every 3 elections all constituency in India would see an all-women electoral candidature for legislative bodies. Now this is more worrying. Not that I am against women, but it is a pure violation of article 15 of our constitution. Prohibition of discrimination on grounds of religion, race, caste, sex or place of birth is the most fundamental essence of any civilized community. Else what separates us from Taliban? Now there is an attempt by state to discriminate men from contesting election (even though it is once in 3 elections). I feel we Indians are not quite sure of what kind of constitution we want. We are running around in circles just like the bill depicted in the cartoonscape.

What is even more worrying is that fact that to uplift women, we actually need to pass a bill. I am quite ashamed that this country does not have many women representing its people. But shouldn't this representation come out of social reforms and change in people's perceptions rather than forced reservation?

Politicians talk about women being oppressed and exploited. They are not given equal opportunity as men. My contention is that only poor are being oppressed and exploited today irrespective of sex. A poor man does not have the same opportunity as that of a rich lady. I don't want to dwell into communism, but the point I want to make is that the approach we are taking will not head this country in right direction.

A better suggestion would be to have reservation of 33% for people living below poverty line. Surely that would be a better reservation policy than on the basis of sex, caste or religion.

A lot of professionals working in big firms are only content with the same mundane work as they are compensated with fat salary, though they are not utilizing their full potential. There are other who jump off the cliff to start a company of their own or work in a startup. If an economist has to term the attitude he would use the term "risk appetite". Both these kinds of employee would try to gauge the "Return of Investment" (ROI) of their efforts and the quality of life they lead or will lead in future. But the quality of life has a major (in my opinion the primary) factor which is "Happiness at work".

As professionals spend a huge percentage of their time at work, it is only imperative that work holds a key for a persons well being. Even if a professional tries to keep personal and work life as discrete as possible, frustrations in one will naturally have an effect over the other. This is because its a innate human nature to be multi faceted constrained with a singular emotional nerve center.

There are no doubt lot of books are written on how to be happy at work. I am not going to tell why or how to be happy at work. I am sure these books would have given lot of pointers for it. I am here to say when people will be happy at work. In my opinion its the culture in the organization, the quality and compatibility of colleagues and the trust they entrust on each other, the team culture and the freedom of space to pursue a persons interest at work (something that should not diverge a lot from the line of work, after all professionals are paid for their time).

If I have to choose one of these factors, I would choose trust. Any relationship is only built on trust. Economy runs mainly on the trust. The very concept of money is trust. But its a sad state where people in a race to be successful have forgotten that the success they are trying to achieve, is nothing but a trust level of all the stakeholders involved. And when people forget that, it will naturally shake the foundation of happiness at work which in turn percolates to personal happiness.

To be happy at work can be a very easy or very difficult depending upon the trust a person places upon himself and others in his team. All other factors are just derivatives of this simple mantra. But though a simple mantra ittakes a long time to derive it. Dr.Manmohan Singh when addressing the world on the recent economic downturn had said "Trust grows like a coconut tree but falls like a coconut". Golden words to be cherished.

I took my family to watch a matinée show of the film 3 Iditots. I thoroughly enjoyed every scene of it and am proud to be a fan of Amir. But one thing that stuck me well was the message conveyed.

To give a brief background on myself, I am from a family full of doctors. My parents, my sister, my sister's husband, my aunt, my uncle everyone of them are doctors. When I had passed out of high school I had a choice of becoming a doctor too. It was taken for granted in my school that I will become a doctor. But I loved solving math problems. I will not forget the day when I laid hands on a computer for the first time in my life. I drew a house in MS paint and immediately wanted to know how it worked. Its the curiosity to know and a passion for math that made me choose Engineering. Boy, was there opposition from my family. It was year 2001 when dot-com bubble burst, when lots of Indians were coming back from US due to lack of opportunity after Y2K. And I became a rebel in the family not to choose the family path.

Today I can say for sure that the decision to pursue my interest and passion has served me well. There was one message that I have learnt late after coming to the industry, one which is conveyed very well. Don't run after success, pursue excellence. A big thanks to 3 idiots team.

I had written a post titled WHY PAY TAXES? where I had poured out my frustration on the tax policies in India. Today I heard a wonderful news. The charitable status of BCCI is revoked. And guess what they have to pay penalty to cheating the Indian public. I am doing happy dance right now.

I only hope that the money got by taxing the richest commercial cricket body in the world is channelized to develop other sports. All in all this news has made my day.

Now I can say I will surely pay my taxes. Thanks.

Its been a years since the carnage in Mumbai. The entire nation was stunned by a handful of youth with sinister intentions. Lot of things were said and done both by the media, the authorities and the people. Respect and homage were paid to the fallen heroes and those who had shown courage at the time of difficulty.

India had taken a stand to pressurize Pakistan to act on its home grown terror infrastructure. A stand that is certainly not new and certainly without a bite. Our prime minister has assured the nation that it will try all it can to persuade Pakistan to take action on the perpetrators of this terror. A cynical side of mine cannot help but wonder how can India achieve it. Let alone to act on a foreign soil, but the lone terrorist who was caught is yet to given a verdict.

If I am asked "Are you angry at the police authorities for lack of security?", I will say I am more angry at the judiciary than the authorities. If a terrorist who is caught with smoke in his gun is yet to be executed, how this country can hold its head among others and say "we are a partner in the global initiative against terror". No doubt the judiciary should not be bogged by emotions, but the judiciary should some day wake up and realize what is been made out of it. They say a justice delayed is justice denied. I cannot agree more.

We all know the 3 pillars of this democracy. The Legislature, Executive and Judiciary should work in tandem they say. I am only feeling sorry today that the 3 pillars has done little justice in this case. We are all helpless Indians as we always were. Its a sad day and a shameful one.

A lot has been said about Git. There are tons of articles written about how cool and efficient this new SCM is. I was already comfortable with all the features of Subversion and was reluctant to move. But then after a strong urging from my colleague Sankara, I thought to give Git a try.

One thing I can say is that its very very rich in features. It makes Subversion look like a small subset of it. Furthermore it keeps the entire repository in my development machine. It has reduced my dependency on network to reach the Subversion by 90%.

So myself and Sankara are planning to convince other (rather lazy) developers in my company to move to Git. As a sampler we are using git-svn. But it has some issues brought about by the Subversion end of thing. But it works great, surely better than just using Subversion client. But we are planning to move the entire code base to git repository for better leverage.

It there is anyone who is starting a new project and is thinking about which SCM to choose from, think no more. Git is the panacea of all the troubles of tracking code. I have been a huge fan of Linus, and he continues to amaze people like me.

I have been keeping a copy of Donald E. Knuth, The Art of Computer Programming as a reference for few years now. The level of attention to detail is just mind boggling. But the entire book is written for a hypothetical architecture which is like a ASM. Its not only frustrating but makes me skip over pages when I find the reading little painful. I naturally resort to wikipedia for pseudo code or algorithm mentioned in the sections of TAOCP. I would like to see a version of TAOCP upgraded to a more contemporary language or base it on better programming/psuedo-code constructs. Even with these drawbacks, without doubt TAOCP is the best source of reference I know of today.

Ordinary citizens with salaried employment hate the TDS. Its a substantial percentage of their income no doubt, and people don't want to part with their hard earned money, especially if the cost of living has more than doubled in past 5 years.

But its a criminal offense to evade tax. So as a ordinary law abiding citizens, we pay our taxes dutifully. But should we?

I don't know how many Indians know the fact that BCCI is registered as non-profit organization. So it is exempt from taxes. How can the law be so dumb? I am just angry that is all. And people say that other sports aren't doing as well as Cricket. I would say make BCCI pay tax for every nickel and use that money to develop other sports. Surely the money that the government gets through this will not be peanuts. There have been initiatives from the government in 2008 to make BCCI pay tax for IPL. But with the financial year over, we are yet to see any tangible results. Sure BCCI would have bought out high rank officials in the always corrupt IT dept.

Why can't I register myself as a charitable person and not pay tax just like BCCI? I seriously like the model followed in Gulf. Bloody public sector should start thinking of breaking even rather than depending on millions of pockets of ordinary citizens.

I am ok with paying taxes as long as right examples are set for me to pay it. Till then I reserve my right to crib.

Man has through the ages sought in vain for an imaginary elixir of life, the divine amirta, to confer immortality. But the true elixir of life lies near to our hands, for it is the commonest of all liquids, plain water. -- Dr.C.V.Raman

Its been a undisputed fact of life and all of the scientific community is going crazy on the great discovery of water on the moon. Sure its nice to know it. But how happy should mankind be of this discovery? Already there are talks of making a settlement in moon becoming a reality in distant future. I may not live the day when humans have made moon their new home. But some part of me is just disgusted with the idea of man settling in moon.

I am a regular follower of "Cartoonscape" in The Hindu. The issue on September,25th couldn't have told the story better.

For me, humans have become a parasite devouring this planet. A handful of us have exploited, abused and raped out mother earth. Now they are in search of a new host to bear the scourge that they have already done to our natural home. We are just mute spectators to it. A mood very well depicted in the picture. I only hope not to see the day when humans have colonized another world. I rather prefer humans going extinct to leave this planet in peace, for other life forms to have their rightful share of space on Earth.

I had been using Eclipse for a long time now. But I had a chance to try out Intellij Idea lately. I instantly fell in love with it. Simply too good. Makes development lot easier and simpler. Though I am facing some problems with keyboard shortcuts (I keep using eclipse shortcuts by habit), I am really impressed. The integration it has with spring, subversion, hibernate, grails, groovy and lot more have made me a Idea fan. I have plans to buy a license for myself. Currently evaluating 9.0 milestone1. Sorry Eclipse, you had been good, but Idea is simply better.

Politicians especially those associated with Congress have a new fashion trend to follow. But just change in clothes in public does not make them Mahatmas. If congress people think they are doing a right thing to be austere, then should we consider that they were not doing the right thing for so long? Why be austere at all?

People are not fools. If a politician prefers jean against a dhothi, even if they cost all same, should any judgment be made on who is more austere? How does being austere have anything to do with the country?

So my dear Congress fellows, if you think that being austere is the way to go, just do it. Don't make a big fuss. All this could have been kept in low profile. But no!! They want people to take notice. Well we are noticing and we are not amused. Just think of making sure the public money is spent properly. We don't bother about how you guys look, or what clothes you wear everyday.

I tried out my friend's Bose Around ear headphone. I was really impressed and wanted to buy one for myself. I tired buying it online, but to my amusement when I search for "bose headphone", most sites are returning results of movies of Rahul Bose or books on Netaji. Its one thing to customize the search results according to the location. But its quite another to show ridiculous results. I finally went to Bose India website to buy the product. But the point here is that I do not have any option of comparing prices between vendors online something that most online portals in Europe and America provides. If the online retailers wants to attract more customers to their sites, they better pull their socks up.

Very neatly put. Imagining 10th dimension in a very simple way.

I am quite impressed with Jonny Lee's work to turn some of the cheapest hardware into some really useful and awesome tools. Simple but very very effective. TED rocks!!!



Pranav from MIT is developing a kind of a technology (that he and his professor choose to call Sixth Sense) to help people take optimal solutions. Whether the invention goes on to become the Sixth Sense is irrelevant to me. This device beats Microsoft's Surface table in all direction. Just awesome!!!

Having reduced the notion of God to a mere paradox in one of my earlier post Does God exist?, I found myself looking for more paradoxes. Here are few that I have come across.

Paradox of Enumeration
Are there as many natural numbers as squares of natural numbers when measured by the method of enumeration?

• The answer is yes, because for every natural number n there is a square number n^2, and likewise the other way around.
• The answer is no, because the squares are a proper subset of the naturals: every square is a natural number but there are natural numbers, like 2, which are not squares of natural numbers.

Barber's Paradox
Suppose there is a town with just one male barber; and that every man in the town keeps himself clean-shaven: some by shaving themselves, some by attending the barber. It seems reasonable to imagine that the barber obeys the following rule: He shaves all and only those men in town who do not shave themselves.

Under this scenario, we can ask the following question: Does the barber shave himself?

Asking this, however, we discover that the situation presented is in fact impossible:

• If the barber does not shave himself, he must abide by the rule and shave himself.
• If he does shave himself, according to the rule he will not shave himself.

Russell's Paradox
Part of fundamental mathematics, Russell's paradox (also known as Russell's antinomy), discovered by Bertrand Russell in 1901, showed that the naive set theory of Frege leads to a contradiction.

Lets us assume Sets can be divided into
a) Self-containing Sets : The set itself is a element of itself
Examples :
i) Set of everything.
ii) Set of every possible set
iii) Set of everthing except "Statue of Liberty"

b) Non Self-containing Sets : The set is not an element of itself
Examples
i) Set of all cars
ii) Set of all statues.

Now consider the following set.
Set of all Non self-containing sets. Is this set self-containing or non self-containing

• If it is non self-containing, then it should be an element of itself. So it will become self-containing.
• If it is a self-containing set, it should be an element of itself. Then it violates the definition that it is a set of all non self-containing sets.

Raven Paradox
This is a lovely paradox which took some time for me to understand.

(1) All ravens are black.

In strict logical terms, via the Law of Implication, this statement is equivalent to:

(2) Everything that is not black is not a raven.

It should be clear that in all circumstances where (2) is true, (1) is also true; and likewise, in all circumstances where (2) is false (i.e. if we imagine a world in which something that was not black, yet was a raven, existed), (1) is also false. This establishes logical equivalence.

Given a general statement such as all ravens are black, we would generally consider a form of the same statement that refers to a specific observable instance of the general class to constitute evidence for that general statement. For example,

(3) Nevermore, my pet raven, is black.

is clearly evidence supporting the hypothesis that all ravens are black.

The paradox arises when this same process is applied to statement (2). On sighting a green apple, we can observe:

(4) This green (and thus not black) thing is an apple (and thus not a raven).

By the same reasoning, this statement is evidence that (2) everything that is not black is not a raven. But since (as above) this statement is logically equivalent to (1) all ravens are black, it follows that the sight of a green apple offers evidence that all ravens are black.

Hangman's paradox
This is another lovely paradox that I have come across.

A judge tells a condemned prisoner that he will be hanged at noon on one weekday in the following week but that the execution will be a surprise to the prisoner. He will not know the day of the hanging until the executioner knocks on his cell door at noon that day. Having reflected on his sentence, the prisoner draws the conclusion that he will escape from the hanging. His reasoning is in several parts. He begins by concluding that if the hanging were on Friday then it would not be a surprise, since he would know by Thursday night that he was to be hanged the following day, as it would be the only day left (in that week). Since the judge's sentence stipulated that the hanging would be a surprise to him, he concludes it cannot occur on Friday. He then reasons that the hanging cannot be on Thursday either, because that day would also not be a surprise. On Wednesday night he would know that, with two days left (one of which he already knows cannot be execution day), the hanging should be expected on the following day. By similar reasoning he concludes that the hanging can also not occur on Wednesday, Tuesday or Monday. Joyfully he retires to his cell confident that the hanging will not occur at all. The next week, the executioner knocks on the prisoner's door at noon on Wednesday — an utter surprise to him. Everything the judge said has come true.

Drinker's paradox
The drinker paradox is a theorem of classical predicate logic that can be stated: "there is someone in the pub such that, if he or she is drinking, then everyone in the pub is drinking".

The proof begins by recognizing it is true that either everyone in the pub is drinking (in this particular round of drinks), or at least one person in the pub isn't drinking.

On the one hand, suppose everyone is drinking. For any particular person, it can't be wrong to say that if that particular person is drinking, then everyone in the pub is drinking — because everyone is drinking.

Suppose, on the other hand, at least one person isn't drinking. For that particular person, it still can't be wrong to say that if that particular person is drinking, then everyone in the pub is drinking — because that person is, in fact, not drinking.

Either way, there is someone in the pub such that, if he or she is drinking, then everyone in the pub is drinking. Hence the paradox.

Richard's Paradox in real numbers
The paradox begins with the observation that certain expressions in English unambiguously define real numbers, while other expressions in English do not. For example, "The real number whose integer part is 17 and whose nth decimal place is 0 if n is even and 1 if n is odd" defines the real number 17.1010101..., while the phrase "London is in England" does not.

Thus there is an infinite list of all English phrases that do define unambiguously a real numbers; arrange this list by length and then dictionary order, so that the ordering is canonical. This yields an infinite list of the corresponding real numbers: r1, r2, ... . Now define a new real number r as follows. The integer part of r is 0, the nth decimal place of r is 1 if the nth decimal place of rn is not 1, and the nth decimal place of r is 2 if the nth decimal place of rn is 1.

The preceding two paragraphs are an expression in English which unambiguously defines a real number r. Thus r must be one of the numbers rn. However, r was constructed so that it cannot equal any of the rn. This is the paradoxical contradiction.

The following shocking video is a marketing pitch to India by Israeli firm Rafael for Python missiles in Aero India 2009 show. The following video is picked from a defense blog Livefist. Hope you all find this amusing as I did.

The following proof to the non-existence of God is given by Melbourne philosopher Douglas Gasking. This is a funny counter-proof for the ontological ‘proof’ of the existence of God devised by St Anselm (1033–1109). Though Gasking has not proved the non-existence of God (Anselm had not proved the existence either) it makes an interesting read. The Gasking's proof is given below.

(1) The creation of the world is the most marvellous achievement imaginable.
(2) The merit of an achievement is the product of (a) its intrinsic quality, and (b) the ability of its creator.
(3) The greater the disability (or handicap) of the creator, the more impressive the achievement.
(4) The most formidable handicap for a creator would be non-existence.
(5) Therefore, if we suppose that the universe is the product of an existent creator, we can conceive a greater being – namely, one who created everything while not existing.
(6) An existing God, therefore, would not be a being than which a greate cannot be conceived, because an even more formidable and incredible creator would be a God which did not exist.
Ergo,
(7) God does not exist.

God a Paradox
Incidentally, omniscience and omnipotence properties that are normally associated to God are mutually incompatible. If God is omniscient, he must already know how he is going to intervene to change the course of history using his omnipotence. But that means he can't change his mind about his intervention, which means he is not omnipotent.
For example, let us assume yesterday God saw the state of the world on 31st December, 2099 by using his power of omniscience. And today, for some reason God wants to change the state of that future world through his power of omnipotence.
a) If he manages to change the world, then what he saw yesterday was not correct. So it negates his omniscience.
b) If he does not manage to change the world (since it violates the power of omniscience as stated above), it would violate God's power of omnipotence.

So a God, who can see everything and can do anything reduces to a mere mathematical paradox. Can such a God exist?