Zakir Naik has become a really famous celebrity in islamic world. His arguments are however flawed and make least sense. Here are my comments on how he justify's the existence of "Allah".

ZAKIR NAIK: Normally, when I meet an atheist, the first thing I like to do is to congratulate him and say, "My special congratulations to you", because most of the people who believe in God are doing blind belief - he is a Christian, because his father is a Christian; he is a Hindu, because his father is a Hindu; the majority of the people in the world are blindly following the religion of their fathers. An atheist, on the other hand, even though he may belong to a religious family, uses his intellect to deny the existence of God; what ever concept or qualities of God he may have learnt in his religion may not seem to be logical to him.

My Muslim brothers may question me, "Zakir, why are you congratulating an atheist?" The reason that I am congratulating an atheist is because he agrees with the first part of the Shahada i.e. the Islamic Creed, 'La ilaaha' - meaning 'there is no God'. So half my job is already done; now the only part left is 'il lallah' i.e. 'but Allah' which I shall do Insha Allah. With others (who are not atheists) I have to first remove from their minds the wrong concept of God they may have and then put the correct concept of one true God.

MY RESPONSE: Thanks Zakir but you will need real proof and not make beliefs to make me believe in your religion or in God.

ZAKIR NAIK: My first question to the atheist will be: "What is the definition of God?" For a person to say there is no God, he should know what is the meaning of God. If I hold a book and say that 'this is a pen', for the opposite person to say, 'it is not a pen', he should know what is the definition of a pen, even if he does not know nor is able to recognise or identify the object I am holding in my hand. For him to say this is not a pen, he should at least know what a pen means. Similarly for an atheist to say 'there is no God', he should at least know the concept of God. His concept of God would be derived from the surroundings in which he lives. The god that a large number of people worship has got human qualities - therefore he does not believe in such a god. Similarly a Muslim too does not and should not believe in such false gods.

MY RESPONSE: These are the two definitions I found in dictionary for the word "God".

1. (in Christianity and other monotheistic religions) the creator and ruler of the universe and source of all moral authority; the supreme being.
 
2. (god) (in certain other religions) a superhuman being or spirit worshiped as having power over nature or human fortunes; a deity : a moon god | an incarnation of the god Vishnu.
 
• an image, idol, animal, or other object worshiped as divine or symbolizing a god.
• used as a conventional personification of fate : he dialed the number and, the gods relenting, got through at once.

ZAKIR NAIK: If a non-Muslim believes that Islam is a merciless religion with something to do with terrorism; a religion which does not give rights to women; a religion which contradicts science; in his limited sense that non-Muslim is correct to reject such Islam. The problem is he has a wrong picture of Islam. Even I reject such a false picture of Islam, but at the same time, it becomes my duty as a Muslim to present the correct picture of Islam to that non-Muslim i.e. Islam is a merciful religion, it gives equal rights to the women, it is not incompatible with logic, reason and science; if I present the correct facts about Islam, that non-Muslim may Inshallah accept Islam.

Similarly the atheist rejects the false gods and the duty of every Muslim is to present the correct concept of God which he shall Insha Allah not refuse.

MY RESPONSE: The picture of Islam that you are rejecting as wrong has xreated this image because of the "Holy" scribblings in your Quran. Here are a few contradictions in Quran:

1. And it just doesn't add up: (*) Surah 4:11-12 and 4:176 state the Qur'anic inheritance law. If a man dies and leaves three daughters, his two parents and his wife then they will receive the respective shares of 2/3 for the 3 daughters together, 1/3 for the parents together [both according to verse 4:11] and 1/8 for the wife [4:12] which adds up to more than the estate available. A second example is, that when a man leaves only his mother, his wife and two sisters, then they receive 1/3 [mother, 4:11], 1/4 [wife, 4:12] and 2/3 [the two sisters, 4:176], which again adds up to 15/12 of the available property. Guess God doesn't know mathematics. Well, what more can you expect from a tyrant. No wonder he is bad at the language of reason.

2. Further numerical discrepancies (*) Does Allah's day equal to 1,000 human years (Surah 22:47, 32:5) or 50,000 human years (Surah 70:4)?

3. Islamic version of what man was made from: A criticism of the Qur'an involves verses 5-7 of surah 86. They claim: Now let man but think from what he is created! He is created from a drop emitted - proceeding between the backbone and the ribs. (86:5-7)
 
This contradicts the scientific fact that semen is produced by the testicles, prostate gland, and seminal vesicles, none of which are between the backbone and the ribs. Critics note that Hippocrates, whose writings were widely available in the pre-Islamic Middle East, had taught that semen passes from the kidneys via the testicles into the penis, and that this is a plausible source for the idea in this verse. Muslim apologist Maurice Bucaille states that these verses are "hardly comprehensible" and finds his own translations of them using meanings not found in dictionaries.
 
And there is a really long list...

ZAKIR NAIK: The methods of proving the existence of God with usage of the material provided in the 'Concept of God in Islam' to an atheist may satisfy some but not all.
Many atheists demand a scientific proof for the existence of God. I agree that today is the age of science and technology. Let us use scientific knowledge to kill two birds with one stone, i.e. to prove the existence of God and simultaneously prove that the Qur'an is a revelation of God.
 
If a new object or a machine, which no one in the world has ever seen or heard of before, is shown to an atheist or any person and then a question is asked, "Who is the first person who will be able to provide details of the mechanism of this unknown object? After little bit of thinking, he will reply, 'the creator of that object.' Some may say 'the producer' while others may say 'the manufacturer.' What ever answer the person gives, keep it in your mind, the answer will always be either the creator, the producer, the manufacturer or some what of the same meaning, i.e. the person who has made it or created it. Don't grapple with words, whatever answer he gives, the meaning will be same, therefore accept it.

MY RESPONSE: Yes, scientific methods of rigour and testing are unfallable like human minds. Scientific method is totally based on evidence and not fairy tales. So are you saying Quran mentions many scientific facts (which I seriously doubt) and thus is a revelation from God. Even an encyclopedia mentions many scietific truths and facts which almost 100% of the population of the Earth doesn't kow. Does that make it a word of God?. No.
 
Your second argument is the "famous" watchmaker argument. Just because everything around you that seems complex was designed by someone even more complex in makeup, then humans and every other living creature (which are incredibily complex in their makeup) mus be made by an even complex creator, God. Following the same argument, it is very logical to ask, who made the so very complex God? Thus there is no end to the regress. Only option out is that life came from very simple beginnings and has evolved in to the complex forms as we see today. 

ZAKIR NAIK: Blah blah.... probability blah bhah,.... guesses are correct blah blah blah.
 
The world that we live on, what's the shape of this earth on which we live? The atheist will tell you it is spherical. When did you come to know? So he will tell us it was 1597 when Francis Drake's when he sailed around the earth and then he proved that the earth was spherical. But Quran says 1400 years ago in Surah Naziat C 79 V 30.  And thereafter we have made the earth egg shape. The Arabic word 'Dahaha' one of which meaning is geological expand. The other meaning is direct from the Arabic word 'Duyah' which means an egg. It doesn't refer to a normal egg. It refers to the egg of an ostrich. We know that the world is not completely round like a ball but it is geo-spherical in shape its flat from the poles and if you analyze the shape of the egg of an ostrich that two is geo-spherical in shape.

MY RESPONSE: Please visit this website: You'll see people had hypothesised a spherical Earth centuries before the Quran was even written.

ZAKIR NAIK: The light of the moon can be its own light or a reflected light. The Qur'an rightly says it is a reflected light. If it is a guess, the chances that it will be correct is 1/2 and the probability that both the guesses i.e the earth is spherical and the light of the moon is reflected light is 1/30 x 1/2 = 1/60.

MY RESPONSE: Quran says: Blessed is He Who made constellations in the skies, and placed therein a Lamp [siraaj] and a Moon giving light [noor] (25:61)
 
It is He Who made the sun to be a shining glory and the moon to be a light [noor] (of beauty), and measured out stages for her; that ye might know the number of years and the count (of time). Nowise did Allah create this but in truth and righteousness. (Thus) doth He explain His Signs in detail, for those who understand. (10:5)
 
See ye not how Allah has created the seven heavens one above another, and made the moon a light [noor] in their midst, and made the sun as a lamp [siraaj]? (71:15-16)
 
I agree with you here that moon light is "reflected" light. But Quran says the moon is place in the midst of 7 heavens. I hope you know man has been to moon and has come back and many unmanned missions have also made it there. Sadly though, no one has ever found any of these heavens or their virgins while travelling through the distance.

ZAKIR NAIK: Further, the Qur'an also mentions every living thing is made of water. Every living thing can be made up of either wood, stone, copper, aluminum, steel, silver, gold, oxygen, nitrogen, hydrogen, oil, water, cement, concrete, etc. The options are say about 10,000. The Qur'an rightly says that everything is made up of water. If it is a guess, the chances that it will be correct is 1/10,000 and the probability of all the three guesses i.e. the earth is spherical, light of moon is reflected light and everything is created from water being correct is 1/30 x 1/2 x 1/10,000 = 1/60,000 which is equal to about .0017%.

MY RESPONSE: Yes every living thing on Earth has water as its major constituent. Even ancient cultures knew that. Hindus and ancient Greeks considered bodies to be made of Earth, Fire, Wind and Water. And far from your logic, living cells ar made also from other elements like hydrogen (which is a constituent of water itself), carbon, potassium, calcium, zinc, iron, copper, etc. Guess your God didn't know that.

ZAKIR NAIK: The Qur'an speaks about hundreds of things that were not known to men at the time of its revelation. Only in three options the result is .0017%. I leave it upto you, to work out the probability if all the hundreds of the unknown facts were guesses, the chances of all of them being correct guesses simultaneously and there being not a single wrong guess. It is beyond human capacity to make all correct guesses without a single mistake, which itself is sufficient to prove to a logical person that the origin of the Qur'an is Divine. Creator is the author of the Qur'an.

The only logical answer to the question as to who could have mentioned all these scientific facts 1400 years ago before they were discovered, is exactly the same answer initially given by the atheist or any person, to the question who will be the first person who will be able to tell the mechanism of the unknown object. It is the 'Creator', the producer, the Manufacturer of the whole universe and its contents. In the English language He is 'God', or more appropriate in the Arabic language, 'Allah'.

MY RESPONSE: Only logic that follows that Quran, like any other religious scripture is full of logical and scientific errors that has nothing to do with sientific approach. It is only for lack of ability to think that people will fall into the stupid religious dogma.

ZAKIR NAIK: Its mentioned in Quran, Mountains are created to prevent Earthquakes. Now we know with latest advances of science that this is actually a fact.

MY RESPONSE: [ROFLMAO] A scientific contradiction critics use is the claim that the quran says mountains were created to prevent earthquakes. In reality, mountians were created as a result of earthquakes, and mountains do not render the earth's crust stable.

And He has set up on the earth mountains standing firm, lest it should shake with you; and rivers and roads; that ye may guide yourselves; (16:15)
 
And We have set on the earth mountains standing firm, lest it should shake with them, and We have made therein broad highways (between mountains) for them to pass through: that they may receive Guidance. (21:31)

Critics say these verses show that the writer of the quran did not know the reason for the creation of mountians. These verses say that mountians were created to prevent earthquakes, while modern geology tells us that mountians were created because of earthquakes and not to prevent them. Mountains are simply folds of Land created when two tectonic plates collide. Simple. And God got it wrong. LOL.

ZAKIR NAIK: When I was in school i had learned that the sun was stationary. It revolves but did not rotate about on its own axis. Then atheist may says 'Is that mentioned in the Quran?' I said 'No that is what I learned in school.' 'And I passed my school in 1982 approximately 12 years back I have learned the sun was stationary did not rotate about on its own axis. But the Quran says in Surah Ambia C 21 V 33. 'It is Allah who created the Night and the Day and the Sun and the Moon. Each one travelling in the orbits with its own motion'. So the Quran says that beside the sun revolving, it even rotates about its own axis. Who could have mentioned that in the Quran 1400 years ago?

MY RESPONSE: First of all, Day is because of presence of sunlight on one part of the Earth and night is absense of light in one part. No one can "create" day and night. Your book says Sun and Moon travell in orbit with their own motion. But no where it mentions Earth travels around the Sun. Infact people at that time considered Sun to revolve arount Earth. Thus it is very much probable that the "Good" book of yours is just portraying God's hand in that myth.

Also the book mentions: Until, when he reached the setting of the sun, he found it set in a spring of murky water: Near it he found a People: We said: "O Zul-qarnain! (thou hast authority,) either to punish them, or to treat them with kindness." (18:86)

And the sun runs his course for a period determined for him: that is the decree of (Him), the Exalted in Might, the All-Knowing. (36:38)

Notable critics claim that these verses are a scientific error since the sun does not actually set in a spring of murky water. [8][9] Muslims respond by stating that this part of the Quran is a narrative from Zul-Qarnain's point of view; and Zul-Qarnain was describing the setting of the sun as he saw it (the sun looked like it set in a spring of water). But I thought Quran was the word of God. Where did this guy's words come into picture?

ZAKIR NAIK: There are hundred of verses in the Quran which only speaks about the water cycles which science has discovered these centuries.

We can keep on talking that today we have come to know that the plants have got sexes which we did not know earlier. Quran says in Surah Taha C 20 V 53 that the plants got sexes, males and females. Today we have come to know that there is two types of water, sweet and salty and there is barrier between them which is mentioned in the Quran in Surah Furqan C 25 V 53 and Surah Rahman C 55 V 19 – 20.  'It is Allah who has let free two bodies of flowing water. Thought they meet they do not mix. There is a barrier between them.' 

Today's science tell us that it is the mountains which prevent the earth from shaking which is mentioning in the Quran 1400 years ago in the Surah Naba C 78 V 6 and 7. The Quran speaks about Biology that we have created every living creature from water. Every living things. In Surah Ambia C 21 V 30. Quran mention this 1400 years ago. The Quran speaks about Zoology about the life-span of the spiders in Surah Ankaburt C 29 V 41. About the ants in Surah Al Namal C 27 V 17 to 18. About the bees in Surah Nahl C 16 V 68-69. The Quran speaks about Embryology in Surah Alaq C 96 V 1-2 . We have created human beings from Alaka (a Leech-like substance) which we have come to know recently. The Quran speaks about the embryological stages in Surah Muminum C 23 V 12 TO 14. You can go on talking about the scientific point there are more than thousands of verses in the Quran which speaks about science. After every scientific facts you ask the question, who could have mention that in the Quran? The only reply the atheist can give you is the creator, the cherisher, the manufacturer, the inventor, the producer. This creator, this manufacturer, this producer, this inventor we Muslim call Him as Allah. That's the reason Francis Bacon, very famous philosopher said 'little knowledge of science takes you away from Almighty God.' In-depth knowledge of science makes you a believer in God. That's the reason today scientists are not eliminating God. The illuminating the models of God 'La ilaha Illal Lah'.

MY RESPONSE: Water cycle was a fact long before quran was written and people knoew about various phases of water. Do you know there are plants and animals that reproduce asexually. Also there are also plants that have both male and female sexes. I guess your God forgot to mention them.

Please open your eyes in light of reason and evidence.

UPDATE: Zakir Naik claims all the life is created from water. Here is a piece of evidence that shows the existence of non-water based life-form.