Short answer
You can reach belief in a Creator by thinking, and that is a real first step. But it is only the first step, and it leaves the largest questions open. What does the Creator want from us? Is wrong forgiven? What follows death? Reason can show that a Maker exists. It cannot tell us His wishes, just as footprints show that someone passed but not where he was going. A wise Maker who made beings able to ask why they are here would be expected to answer them. The Qur'an asks the same question (23:115; 75:36). Many messages claim to be that answer, so the sensible course is to test them, not to refuse them all.
Full explanation
What reason can reach, and what it cannot
Many people reach belief in a Creator by thinking. They see that something exists, that it is ordered, and that minds exist inside it. Those reasons are set out on the pages on how we know God (﷾) exists and who created God (﷾). This page starts after that step. Suppose the Creator exists. Reason then faces questions about His will, not about His existence. What does He ask of us? Is wrong forgiven, and how? What is owed to Him for life itself? What happens at death? Footprints show that someone passed. They do not show where he was going or what he wants. In the same way, a Maker's works show that He exists, but only the Maker can say what He wants. A message is how He would say it. So the real question is not whether a message would be needed. It is whether any message is true. The Qur'an records people who, asked who created the heavens and the earth, answered "Allah". It still asks how they are turned away from the truth (29:61). Knowing that a Maker exists is not yet knowing what He asks.
“Were they created of nothing, or were they themselves the creators? Or did they create the heavens and the earth? Nay, they have no firm belief.”
“If indeed thou ask them who has created the heavens and the earth and subjected the sun and the moon (to his Law), they will certainly reply, "Allah". How are they then deluded away (from the truth)?”
What conscience and the world do tell us
Conscience is real, and the Qur'an agrees that every soul is given a sense of right and wrong. The deist believes in a Maker but in no message, and says that conscience and the world are enough. They tell us a great deal. Conscience tells us that kindness is good and cruelty is bad. The world tells us that a wise Maker exists. They do not tell us everything. Sincere people with clear consciences have disagreed about what justice demands, and each was sure. A message does not end every disagreement, and Muslims differ on details too. What it settles are the foundations: whom to worship, what He asks in the main, whether wrong is forgiven and what follows death. Conscience is also silent on whether a wrong done to God (﷾) is forgiven, and on whether life goes on after death. Whether conscience alone can settle right and wrong has its own page.
“By the Soul, and the proportion and order given to it; And its enlightenment as to its wrong and its right;-”
Why a wise Maker would be expected to speak
The reasons that lead to a Maker also describe Him as wise and purposeful. He made an ordered world and minds able to understand it. He also made beings who ask why they are here and who feel that some things ought to be done. It is more reasonable to expect a wise Maker to answer such beings than to make them able to ask and then stay silent. This is an expectation, not a proof. It does not say which message is His. It says only that a message is what a wise Maker would be expected to give, so every claim to be one deserves a hearing.
“Were they created of nothing, or were they themselves the creators? Or did they create the heavens and the earth? Nay, they have no firm belief.”
Islam says the same: you were not made for nothing
The Qur'an puts the same question. It asks whether people think they were made in jest and would never be brought back to account (23:115). It asks whether man thinks he will be left without purpose (75:36). Ibn Kathir reads the first as asking whether people thought they were made without purpose or wisdom. He ties it to the second. For the second he reports that Mujahid and al-Shafi'i read it as: not left uncommanded and unforbidden. He holds that the verse also means man is not left in the grave without being raised.
“"Did ye then think that We had created you in jest, and that ye would not be brought back to Us (for account)?"”
“Does man think that he will be left uncontrolled, (without purpose)?”
Reads the question as asking whether people thought they were created for nothing, without purpose and without any wisdom on God's part, and that they would not return to Him in the Hereafter. He ties it to 75:36, which asks whether man thinks he will be left to himself.
Reports two early readings of "left to himself". Al-Suddi says it means not raised again. Mujahid, al-Shafi'i and Abd al-Rahman ibn Zayd ibn Aslam say it means not commanded and not forbidden. Ibn Kathir holds that the verse covers both. Man is not left in this world without command and prohibition, and he is not left in the grave without being raised and gathered to God.
A messenger to every people
The Qur'an says God (﷾) sent messengers so that people would have no plea against Him (4:165). It says every people had one (10:47), with the same call to serve Allah (﷾) and avoid evil (16:36). Ibn Kathir reads this as a call to worship God (﷾) alone, which every messenger brought. No one is punished before a messenger has come to warn him (17:15). So the Qur'an does not picture a Maker who left most of mankind without guidance.
“Messengers who gave good news as well as warning, that mankind, after (the coming) of the messengers, should have no plea against Allah: For Allah is Exalted in Power, Wise.”
“To every people (was sent) a messenger: when their messenger comes (before them), the matter will be judged between them with justice, and they will not be wronged.”
“For We assuredly sent amongst every People a messenger, (with the Command), "Serve Allah, and eschew Evil": of the People were some whom Allah guided, and some on whom error became inevitably (established). So travel through the earth, and see what was the end of those who denied (the Truth).”
Explains the verse: God sent a messenger to every generation and every group of people. All of them called to the worship of God and forbade the worship of anything besides Him. The worship of others first arose among the children of Adam in the people of Noah. From then on God kept sending messengers with this call. Noah was the first messenger God sent to the people of the earth, and God sealed the messengers with Muhammad (ﷺ). His call reached mankind and jinn, east and west. He cites 21:25 with it.
“Who receiveth guidance, receiveth it for his own benefit: who goeth astray doth so to his own loss: No bearer of burdens can bear the burden of another: nor would We visit with Our Wrath until We had sent a messenger (to give warning).”
"Man-made" is a conclusion, not a starting point
Some claims to speak for God (﷾) are certainly human inventions. Such a claim is easy to make. That is a reason to test the claims, not to refuse all of them. Forged banknotes do not make every note fake. Each note is checked, and a claim to come from God (﷾) can be checked too. Ask what it says about God (﷾) and whether it contradicts itself. Ask whether it has been kept, and whether it carries a sign that can still be examined. Thomas Paine, the 18th-century English-American writer, called every national church a human invention. He reached that as a conclusion about all of them, and each claim still has to be tested one by one.
A deist's case against revealed religion. In chapter 1 Paine states that he believes in one God and hopes for happiness beyond this life. He calls every national church, whether Jewish, Christian or Turkish (his word for the Muslim church), a human invention. In chapter 2 he argues that a revelation is revelation only to the person who receives it, and hearsay to everyone else. His examples there include the Qur'an: he says he did not see the angel himself, and so has a right not to believe the account. In chapter 9 he argues that the creation is the word of God, and that it reveals to man all that is necessary to know of God.
The Qur'an asks to be tested
The Qur'an invites the test. It says that had the book come from anyone but Allah (﷾), people would find much discrepancy in it (4:82). It tells the doubter to produce a sura, a chapter, like it (2:23). It also warns against following what one has no knowledge of (17:36). Islam does not ask for belief with the mind switched off. The page on how to tell if a holy book comes from God (﷾) sets out the tests, and they apply to every book alike.
“Do they not consider the Qur'an (with care)? Had it been from other Than Allah, they would surely have found therein Much discrepancy.”
“And if ye are in doubt as to what We have revealed from time to time to Our servant, then produce a Sura like thereunto; and call your witnesses or helpers (If there are any) besides Allah, if your (doubts) are true.”
“And pursue not that of which thou hast no knowledge; for every act of hearing, or of seeing or of (feeling in) the heart will be enquired into (on the Day of Reckoning).”
What the message adds: belief, worship and character together
Islam does not offer a belief on its own. It joins belief in God (﷾) with prayer, giving, keeping one's word and patience in hardship (2:177). The whole of life is lived in answer to the Maker. This is what a message adds to belief. It tells us what He wants, and it gives a way of life that follows from knowing Him.
“It is not righteousness that ye turn your faces Towards east or West; but it is righteousness- to believe in Allah and the Last Day, and the Angels, and the Book, and the Messengers; to spend of your substance, out of love for Him, for your kin, for orphans, for the needy, for the wayfarer, for those who ask, and for the ransom of slaves; to be steadfast in prayer, and practice regular charity; to fulfil the contracts which ye have made; and to be firm and patient, in pain (or suffering) and adversity, and throughout all periods of panic. Such are the people of truth, the Allah-fearing.”
The replies answered
The Age of Reason, Part I (1794)
A deist's case against revealed religion. In chapter 1 Paine states that he believes in one God and hopes for happiness beyond this life. He calls every national church, whether Jewish, Christian or Turkish (his word for the Muslim church), a human invention. In chapter 2 he argues that a revelation is revelation only to the person who receives it, and hearsay to everyone else. His examples there include the Qur'an: he says he did not see the angel himself, and so has a right not to believe the account. In chapter 9 he argues that the creation is the word of God, and that it reveals to man all that is necessary to know of God.
Cited for
The creation is God's word to all people. It reveals all that is necessary to know of God, so no book is needed.
The response
Creation shows a Maker, and Islam agrees that it speaks to everyone. What it does not show is His will. Does He forgive wrong? What does He ask? What follows death? Paine only hoped for happiness beyond this life. A hope is not an answer. Only the Maker can say.
Where it lands — Creation answers whether there is a Maker. It leaves open what He wants, and that is what a message is for.
Qur'an 91:7-8 — Surat al-Shams (The Sun), verses 7-8
“By the Soul, and the proportion and order given to it; And its enlightenment as to its wrong and its right;-”
Cited for
Conscience is the guidance God gave every person. It tells us right from wrong without any book.
The response
Islam agrees that conscience is given to every soul (91:7-8). It tells us that right and wrong exist. It does not settle the details, and sincere people with clear consciences have disagreed on them. A message does not end every disagreement, and Muslims differ on details too. What it settles are the foundations: whom to worship, what He asks in the main, whether wrong is forgiven and what follows death.
Where it lands — Conscience is a gift and a witness, but it is not the whole answer. The question of what conscience can settle has its own page.
Belief without Borders (2014)
A theologian's study based on interviews with about 100 Americans who call themselves spiritual but not religious. It finds that, in general, they do not believe in an interventionist or personal God, and that they place spiritual authority in the individual rather than in a community or tradition.
Cited for
Many who are spiritual but not religious do not believe in a God who intervenes. A message would be such an intervention, so there is none.
The response
The usual reason for that view is that the world runs by steady laws. Laws of nature describe what happens when nothing beyond nature acts. They cannot forbid their own Maker to act. Speaking to a mind is a far smaller thing than making the world. The Qur'an asks whether a Maker who made beings able to ask why they are here would leave them without purpose (23:115; 75:36).
Where it lands — Steady laws do not bind their Maker. Silence is the stranger design for a wise Maker.
Qur'an 10:47 — Surat Yunus (Jonas), verse 47
“To every people (was sent) a messenger: when their messenger comes (before them), the matter will be judged between them with justice, and they will not be wronged.”
Cited for
A message to one people at one time is unfair to everyone else. A just God would not choose such a way.
The response
The Qur'an does not say that. It says a messenger was sent to every people (10:47), with the same call to serve Allah (16:36). No one is punished before the message has reached him (17:15). Messengers came so that no one has a plea against God (4:165).
Where it lands — On Islam's account no people were left without a messenger, and no one is judged before the message reaches him.
The Age of Reason, Part I (1794)
A deist's case against revealed religion. In chapter 1 Paine states that he believes in one God and hopes for happiness beyond this life. He calls every national church, whether Jewish, Christian or Turkish (his word for the Muslim church), a human invention. In chapter 2 he argues that a revelation is revelation only to the person who receives it, and hearsay to everyone else. His examples there include the Qur'an: he says he did not see the angel himself, and so has a right not to believe the account. In chapter 9 he argues that the creation is the word of God, and that it reveals to man all that is necessary to know of God.
Cited for
Revelation is hearsay to everyone but the first person who received it. No one is bound to believe a report.
The response
Paine's own example was the Qur'an. He had not seen the angel, so he would not believe. But the Qur'an does not ask to be believed on a report of the angel alone. The text itself is here, and its challenge to produce a sura like it can be tested by anyone today (2:23; 17:88). Reports of the past are weighed, not dismissed, and this one comes with the book in hand.
Where it lands — Hearsay is a reason to examine a report, not to dismiss it. The Qur'an asks to be examined.
Qur'an 2:23 — Surat al-Baqara (The Cow), verse 23
“And if ye are in doubt as to what We have revealed from time to time to Our servant, then produce a Sura like thereunto; and call your witnesses or helpers (If there are any) besides Allah, if your (doubts) are true.”
Cited for
Every religion claims God's authority, and each accuses the others of error. So all of them are human inventions.
The response
Rival claims show that some are wrong. They do not show that all are. Forged banknotes do not make every note fake. The way to find out is to test each claim, and the Qur'an offers itself for that test (2:23; 4:82).
Where it lands — "Man-made" has to be shown claim by claim. It cannot be assumed of all of them.
Qur'an 17:36 — Surat al-Isra (The Night Journey), verse 36
“And pursue not that of which thou hast no knowledge; for every act of hearing, or of seeing or of (feeling in) the heart will be enquired into (on the Day of Reckoning).”
Cited for
Each person is the only authority on what is true about God. An outside message cannot bind him.
The response
No one can believe for another, and Islam does not ask for blind belief. It tells the reader not to follow what he has no knowledge of (17:36) and to weigh the book (4:82). Judging a message is not the same as deciding for oneself what God (﷾) wants.
Where it lands — Islam asks each person to judge the message. It does not ask him to set judgement aside.
Qur'an 2:177 — Surat al-Baqara (The Cow), verse 177
“It is not righteousness that ye turn your faces Towards east or West; but it is righteousness- to believe in Allah and the Last Day, and the Angels, and the Book, and the Messengers; to spend of your substance, out of love for Him, for your kin, for orphans, for the needy, for the wayfarer, for those who ask, and for the ransom of slaves; to be steadfast in prayer, and practice regular charity; to fulfil the contracts which ye have made; and to be firm and patient, in pain (or suffering) and adversity, and throughout all periods of panic. Such are the people of truth, the Allah-fearing.”
Cited for
Organised religion brings hypocrisy and control, so faith is better kept private.
The response
People do misuse religion. The Qur'an says that turning the face east or west is not righteousness, and it lists belief, giving, prayer, kept promises and patience (2:177). Misuse by some shows that people fail. It does not show that God (﷾) sent no message.
Where it lands — The failures of followers are a reason to examine the message, and the Qur'an sets a standard that empty form does not meet.
Perspectives
Deism: a Maker, but no message
God made the world and speaks to everyone through it. The creation cannot be forged, lost or mistranslated, and it tells us all we need to know of God. A message to one man at one time is only hearsay to everyone else. A God who wanted all to know Him would not choose such a way.
Thomas Paine, The Age of Reason, Part I (1794)
The creation is the word of God, and it reveals to man all that is necessary to know of God. No book adds anything.
Rebuttal
Grant that creation points to a Maker and speaks to everyone. It does not say what He asks, or whether wrong is forgiven. Paine himself only hoped for happiness beyond this life. The Qur'an asks whether man was made without purpose (23:115; 75:36).
Every national church claims a special mission from God, as if the way to God were not open to every man alike. That would be unfair to the rest.
Rebuttal
Grant that God's (﷾) way must be open to all. The Qur'an says a messenger was sent to every people with one call (10:47; 16:36). No one is punished before it reaches him (17:15).
A revelation is revelation only to the person who receives it. To everyone else it is hearsay, so no one is bound to believe it.
Rebuttal
Paine grants that God (﷾) can speak to a person. Hearsay is a reason to examine a report, not to dismiss it. The Qur'an does not rest on report alone: its text and its challenge are here to test (2:23; 17:88).
Human language is local and changeable, so God would not use it to reach all people. He speaks through the creation instead.
Rebuttal
Grant that languages differ. The Qur'an says each messenger taught in the language of his own people (14:4). Each brought the same call to serve Allah (16:36).
Spiritual, not religious
Awe, gratitude and a sense of something greater are real, and they need no creed. Each person is the best judge of what is true for him. A fixed set of beliefs and practices only adds division and control.
Linda A. Mercadante, Belief without Borders (2014), on people who describe themselves this way
A personal sense of the divine is enough. No fixed beliefs or practices are needed.
Rebuttal
Grant that awe and gratitude are real and worth having. A feeling cannot tell us what the Maker wants. Only the Maker can say (23:115; 75:36).
Each person is the final authority on what is true about God, so no outside message can bind him.
Rebuttal
Grant that each person must judge for himself. Judging is what the Qur'an asks: weigh the book and follow only what you know (4:82; 17:36). Judging a message is not the same as deciding what God (﷾) wants.
Organised religion brings hypocrisy and control, so it is better to keep faith private.
Rebuttal
Grant that people misuse religion. The Qur'an itself says that empty form is not righteousness (2:177). Misuse by some does not show that God (﷾) sent no message.
All religions are man-made
Every religion began among particular people at a particular time, and each claims a special mission from God. Paine wrote that every national church, Jewish, Christian or Turkish (his word for Muslim), is a human invention. So belief in God should not depend on any of them.
Thomas Paine, The Age of Reason, Part I (1794)
Every religion claims a special mission from God, and each accuses the others of error. So all of them are likely human inventions.
Rebuttal
Grant that people have claimed God's (﷾) authority falsely. Rival claims show that some are wrong, not that all are. Each claim can be tested (4:82; 2:23).
The Islamic perspective
A Maker who is wise would not make beings able to ask why they are here and leave them without an answer. The Qur'an asks the same question, says a messenger came to every people, and invites everyone to test its claim. Islam gives belief, worship and character together as one way of life.
The Qur'an asks whether people think they were created in jest and would not be brought back. It asks whether man thinks he will be left without purpose.
Ibn Kathir holds that 75:36 covers both readings. Man is not left in this world without command and prohibition. He is not left in the grave without being raised.
God (﷾) sent a messenger to every people with the call to serve Allah (﷾) and avoid evil. So no one has a plea against Him.
No one is punished before a messenger has come to warn him.
The Qur'an invites testing. It says that from anyone but Allah (﷾) it would show much discrepancy. It challenges the doubter to produce a sura like it, and warns against following what one has no knowledge of.
Islam joins belief in God (﷾) with prayer, giving, keeping one's word and patience. So all of life is lived in answer to the Maker.