Short answer
Only as far as God, who alone knows all things, makes it known. Jain teaching holds that only one who knows all things sees the whole truth. It says Mahavira, the last Tirthankara (teacher), became such a knower. A scripture of the Svetambaras, one main Jain tradition, says he "knew and saw all conditions of all living beings in the world". The Jain teaching of many aspects, anekantavada, adds that anyone short of that knowledge sees only part. But Jains hold that, in this part of the world, no one reaches that knowledge in this age. They rely on books that both Jain traditions say were partly lost, and that they do not share. Islam teaches that no creature, not even a prophet, knows all things. God (﷾) revealed the Qur'an to the Prophet Muhammad (ﷺ), who conveyed it, and God (﷾) promised to guard it.
Full explanation
The Jain starting point: one who knows all
Jains hold that Mahavira, the last Tirthankara, or Jina, became a Kevalin, an all-knowing one. The Kalpa Sutra is a scripture of the Svetambaras, one of the two main Jain traditions. It says he "knew and saw all conditions of all living beings in the world". The Acaranga, also Svetambara, says the same. The Digambaras, the other main tradition, hold this teaching from their own books. The Jain scholar Padmanabh Jaini describes this knowledge as awareness of every existing thing in all its qualities and states. He cites a Digambara work, Amritacandra's Tattvarthasara. So Jain teaching holds that the whole truth exists, and that one who knows all things sees it.
“he the Arhat, for whom there is no secret, knew and saw all conditions of all living beings in the world, what they thought, spoke, or did at any moment.”
“he saw and knew all conditions in the whole world of all living beings.”
Jaini describes kevala, the highest of the five kinds of knowledge in Jain teaching, as absolute omniscience, involving awareness of every existent thing in all its qualities and modes (states) (p. 122). For this he cites, in Sanskrit, a Digambara work, Amritacandra's Tattvarthasara 1.30-31, whose words describe kevala knowledge as unaided (asahaya), unobstructed (niravarana) and reaching all things (sarvabhavaga) (p. 122, n. 43). He explains that omniscience (kevalajnana) is the perfected state of the soul's own quality of knowledge (p. 91).
Many aspects: why a partial view falls short
Jain teachers hold that every thing has countless qualities and changing states. So an ordinary person, who is not all-knowing, cannot see a thing in its entirety. This is anekantavada, the teaching of many aspects. A partial view is called a naya, a standpoint. A naya is valid as a partial view. It becomes false when it is held as the whole truth, which Jains call ekanta, one-sidedness. Siddhasena Divakara, whom both traditions claim, wrote a treatise on this. Syadvada adds the word syat, "in some respect", to a statement to show the respect in which it holds.
Jaini explains that, in Jain teaching, every existent thing is a substance with qualities, and the qualities pass through changing modes. Because the qualities are innumerable and their modes infinite, it is not possible for an ordinary, non-omniscient person to perceive an existent thing in its entirety. The Jain term anekanta, manifold aspects, expresses this complexity (p. 91). Jains claim that non-Jain systems are defective because they view being in only a single aspect (ekanta), for example as only eternal or only changing (pp. 91-92). The doctrines of other schools are invariably described as wrong because they are one-sided, though Jains hold that from the proper perspective they can be fitted into the Jain system (p. 90).
Jaini writes that, in condemning other schools as one-sided, the Jain does not say their views are totally wrong. They are valid when seen as nayas, partial expressions of truth, and become false only when held to have absolute and exclusive validity (p. 93). His note quotes, in Sanskrit, the Svetambara Mallisena's commentary on verse 28 of Hemacandra's Anyayogavyavacchedika. Its words say that "it exists" (sat) is a naya, while "it only exists" (sad eva) is a durnaya, a faulty naya, which sets aside the thing's other properties (p. 93, n. 8). Syadvada qualifies a statement with syat, best rendered "in some respect", and eva, "in fact" (p. 94).
Jaini writes that Siddhasena Divakara (fifth century), a writer claimed equally by both Jain traditions, wrote the Sanmati-sutra. This short Prakrit treatise seeks to establish that the various viewpoints (naya) are valid when approached in the spirit of syadvada, and not valid when put forth in the absolutist (ekanta) manner of non-Jain systems. Jaini adds that the Mimamsakas, Hindu defenders of the Vedas, took great exception to the Jain claim that human Jinas are omniscient (p. 83).
Not a teaching that every religion is right
Anekantavada is often summed up today as "every view is partly true, so every religion is right". Classical Jain teachers did grant that rival views hold part of the truth, as partial views. Jaini writes that such views become false when held as the whole truth. Paul Dundas, a scholar of Jainism, writes that the teaching grew in part from the claim that the Tirthankaras were fully omniscient. Jain logicians used it to show that Hindu and Buddhist systems were one-sided. The Svetambara commentator Mallisena calls a view that asserts one aspect only a faulty view. Dundas adds that reading the teaching as tolerance of every opinion is modern. He writes that Jainism has consistently held its own path superior to others.
Jaini writes that, in condemning other schools as one-sided, the Jain does not say their views are totally wrong. They are valid when seen as nayas, partial expressions of truth, and become false only when held to have absolute and exclusive validity (p. 93). His note quotes, in Sanskrit, the Svetambara Mallisena's commentary on verse 28 of Hemacandra's Anyayogavyavacchedika. Its words say that "it exists" (sat) is a naya, while "it only exists" (sad eva) is a durnaya, a faulty naya, which sets aside the thing's other properties (p. 93, n. 8). Syadvada qualifies a statement with syat, best rendered "in some respect", and eva, "in fact" (p. 94).
Dundas writes that the Jain teaching of manypointedness (anekantatva) grew from two factors: the claim of full omniscience for the Tirthankaras, the teachers who pass on a correct understanding of reality to the unenlightened, and the view that reality involves both permanence and change. Any judgement made by a soul that is not omniscient is adequate for everyday purposes but inevitably flawed. Each naya, or standpoint, is incomplete on its own. Syadvada, the doctrine of "may be", was not a form of scepticism for Jain philosophers. In Jain hands the method became a weapon of debate, used to show that Hindu and Buddhist systems were one-sided. In the Jain argument, such systems genuinely contain partial versions of the truth, but cannot do full justice to the many-sided nature of the world. The Svetambara teacher Haribhadra wrote one of its best-known treatises, and never gave up his upholding of the supremacy of Jainism.
Dundas writes that, in modern times, many Jains have come to read manypointedness as an extension of non-violence to tolerance of other people's opinions. He calls this a well-meant misreading of a doctrine that was not intended to promote a universal religious tolerance. He notes that Indian religions were highly critical of their rivals' systems. The Digambara scholar Todarmal (eighteenth century) held that no one from another religious tradition could reach the correct attitude (samyaktva) needed for liberation. Jainism's consistent stance, Dundas writes, is that it is at the most profound level different from and superior to other paths.
How the Jina's knowledge reaches people now
Jaini writes that the authority of Jain teaching rests on the fact that an all-knowing being preached it. But Mahavira, the last Jina of this age in this part of the world, has passed beyond rebirth and teaches no more. A Svetambara scripture says the perfected souls reside at the top of the world. Jains hold that twenty other Jinas teach now, but only in distant regions such as Mahavideha. The best known of them is Simandhara. Svetambara scriptures describe being reborn in Mahavideha and reaching omniscience there. But Jains came to hold that, after Mahavira's disciple Jambu, no one in this part of the world reaches omniscience in this age. So Jains here know the Jina's teaching only through the books handed down. Both traditions say the oldest of those books, the fourteen Purvas, were lost. The Digambaras hold that the Angas, the main books, were lost as well.
Jaini writes that the authority of the Jain teachings rests ultimately on the fact that they were preached by an omniscient being. Jain teachers claim that only the teachings of the Jina can stand the scrutiny of reason (p. 89).
“There at the top of the world reside the blessed perfected souls, rid of all transmigration, and arrived at the excellent state of perfection.”
Dundas writes that, as Jain tradition came to accept that enlightenment was no longer possible in the region of Bharata (India) after the death of Mahavira's disciple Jambu, the Svetambara scriptures came to describe being reborn in the distant region of Mahavideha and reaching enlightenment there. A Svetambara scripture, the Exposition of Explanations, says time is stable in Mahavideha, with no corrupt world age, and that fordmakers (Tirthankaras) preach there. Jains hold that at this moment twenty fordmakers, the 'wandering ones' (viharamana), live and teach in distant regions of the Middle World, the part of the universe where humans live; four of them are in Mahavideha. The most popular is Simandhara. Devotion to him is widespread among Svetambaras, and the tenth-century Digambara Devasena was the first writer to tell that Kundakunda gained his knowledge directly from him.
Dundas writes that, by around the early common era, Jains recognised that a variety of advanced spiritual attainments, of which enlightenment (full omniscience) was one, were no longer possible in this era after the death of the disciple Jambu. Religious practice then aimed not only at burning away karma but also, increasingly, at gaining merit for a good rebirth (chapter 6, opening page, p. 94).
“we are told by the Svetambaras, as well as the Digambaras, that besides the Angas, there existed other and probably older works, called Purvas, of which there were originally fourteen. The knowledge of these Purvas was gradually lost, till at last it became totally extinct.”
“the Digambaras also have lost the Purvas, and the Angas to boot”
Islam's answer: from the All-Knowing, guarded by Him
In Islam, only God (﷾) knows all things. "With Him are the keys of the unseen, the treasures that none knoweth but He" (6:59). No creature knows all things, not even a prophet. The Prophet (ﷺ) was told to say that he did not know the unseen (7:188). God (﷾) makes known what He wills of His unseen to "a messenger whom He has chosen" (72:26-27). So the Prophet (ﷺ) knew of the unseen only what God (﷾) taught him, and he conveyed it. People are given only "a little" knowledge (17:85). They grasp nothing of His knowledge "except as He willeth" (2:255). God (﷾) sent the Qur'an down and promised to guard it (15:9). The Prophet (ﷺ) has died, but the One who guards the Book lives forever. When the Prophet (ﷺ) died, Abu Bakr told the people that Allah (﷾) is alive and never dies. A Jain who seeks the whole truth is invited to read the Qur'an. He or she is also invited to learn about the last Prophet (ﷺ), to whom it was revealed.
“With Him are the keys of the unseen, the treasures that none knoweth but He. He knoweth whatever there is on the earth and in the sea. Not a leaf doth fall but with His knowledge: there is not a grain in the darkness (or depths) of the earth, nor anything fresh or dry (green or withered), but is (inscribed) in a record clear (to those who can read).”
“Say: "I have no power over any good or harm to myself except as Allah willeth. If I had knowledge of the unseen, I should have multiplied all good, and no evil should have touched me: I am but a warner, and a bringer of glad tidings to those who have faith."”
“"He (alone) knows the Unseen, nor does He make any one acquainted with His Mysteries,- "Except a messenger whom He has chosen: and then He makes a band of watchers march before him and behind him,”
“They ask thee concerning the Spirit (of inspiration). Say: "The Spirit (cometh) by command of my Lord: of knowledge it is only a little that is communicated to you, (O men!)"”
“Allah! There is no god but He,-the Living, the Self-subsisting, Eternal. No slumber can seize Him nor sleep. His are all things in the heavens and on earth. Who is there can intercede in His presence except as He permitteth? He knoweth what (appeareth to His creatures as) before or after or behind them. Nor shall they compass aught of His knowledge except as He willeth. His Throne doth extend over the heavens and the earth, and He feeleth no fatigue in guarding and preserving them for He is the Most High, the Supreme (in glory).”
“We have, without doubt, sent down the Message; and We will assuredly guard it (from corruption).”
Aisha reports that when the Prophet (ﷺ) died, Umar insisted he was not dead. Abu Bakr came, kissed the Prophet's face, then told the people that whoever worshipped Muhammad should know Muhammad was dead, and whoever worshipped Allah should know Allah is alive and never dies. He recited 39:30 and 3:144, that Muhammad is no more than a messenger, and the people wept.
The replies, answered
Qur'an 7:188 — Surat al-A'raf (The Heights), verse 188
“Say: "I have no power over any good or harm to myself except as Allah willeth. If I had knowledge of the unseen, I should have multiplied all good, and no evil should have touched me: I am but a warner, and a bringer of glad tidings to those who have faith."”
Cited for
Jain teaching rests on a teacher who knew all things. Islam's Prophet (ﷺ) said he did not know the unseen. So the Jina's teaching stands on firmer ground.
The response
Islam teaches that no creature, not even a prophet, knows all things. The Qur'an says none in the heavens or on earth, except God (﷾), knows what is hidden (27:65). God (﷾) makes known what He wills of His unseen to a messenger He has chosen (72:26-27). So the Prophet (ﷺ) knew of the unseen only what God (﷾) taught him. The Qur'an says he did not speak from his own desire: "It is no less than inspiration sent down to him" (53:3-4). The Qur'an's authority rests on the All-Knowing Himself, not on the knowledge of any man.
Where it lands — In Islam, the source of the message is God, who knows all things. The Prophet (ﷺ) conveyed it as it was sent down to him.
Qur'an 2:106 — Surat al-Baqara (The Cow), verse 106
“None of Our revelations do We abrogate or cause to be forgotten, but We substitute something better or similar: Knowest thou not that Allah Hath power over all things?”
Cited for
Critics say the Qur'an also lost verses, through abrogation, so Muslims face the same problem as the Jains.
The response
In 2:106 God (﷾) says that whatever verse He abrogates or causes to be forgotten, He replaces with something better or similar. In 87:6-7 He tells the Prophet (ﷺ) he will not forget, except as God (﷾) wills. So any removal is God's (﷾) own act, stated in the Book itself. The Jain traditions report loss among the followers, after Mahavira had died. Zayd wrote the revelation for the Prophet (ﷺ), and Gabriel reviewed the Qur'an with him each year.
Where it lands — What God (﷾) removed, He removed in the Prophet's (ﷺ) lifetime, by His own word. That is not teaching lost among followers after the teacher died.
Jaini, The Jaina Path of Purification (1979), pp. 93-94
Jaini writes that, in condemning other schools as one-sided, the Jain does not say their views are totally wrong. They are valid when seen as nayas, partial expressions of truth, and become false only when held to have absolute and exclusive validity (p. 93). His note quotes, in Sanskrit, the Svetambara Mallisena's commentary on verse 28 of Hemacandra's Anyayogavyavacchedika. Its words say that "it exists" (sat) is a naya, while "it only exists" (sad eva) is a durnaya, a faulty naya, which sets aside the thing's other properties (p. 93, n. 8). Syadvada qualifies a statement with syat, best rendered "in some respect", and eva, "in fact" (p. 94).
Cited for
Islam's claim that it alone is true is the very one-sidedness (ekanta) that Jain logic calls false.
The response
In Jain logic, ekanta is a partial view held as if it were the whole. Jain teachers found that fault in rival systems, not in the Jina's own teaching. They held that only the Jina's teaching can stand the scrutiny of reason. So Jain logic itself allows one teaching to be the true one, if it comes from one who knows all things. Islam's claim is of that kind: the Qur'an comes from God (﷾), who knows all things (6:59). And the Qur'an invites the test: a book from other than God (﷾) would hold much discrepancy (4:82).
Where it lands — Claiming the truth is not ekanta when the claim is that the word comes from the One who knows all things. The question is whether the Qur'an is that word, and the Qur'an invites the test.
Kalpa Sutra §121 — Lives of the Jinas, §121
“he the Arhat, for whom there is no secret, knew and saw all conditions of all living beings in the world, what they thought, spoke, or did at any moment.”
Cited for
The Jina's knowledge reaches us through his disciples and the teachers who came after them.
The response
Through which books? Both traditions say the fourteen Purvas were lost. The Digambaras hold that the Angas were lost as well. They do not admit that the Svetambara Angas survive in authentic form. Both accept Umasvati's Tattvartha Sutra, but it is a teacher's summary. A shared summary is not a shared record of the Jina's words. Knowledge that was once whole is only as sure as the record that carries it.
Where it lands — The Jina's knowledge reaches Jains today through canons that are partly lost and that the two traditions do not share.
Dundas, The Jains (2002), chapter 6
Dundas writes that, by around the early common era, Jains recognised that a variety of advanced spiritual attainments, of which enlightenment (full omniscience) was one, were no longer possible in this era after the death of the disciple Jambu. Religious practice then aimed not only at burning away karma but also, increasingly, at gaining merit for a good rebirth (chapter 6, opening page, p. 94).
Cited for
A Jain needs no messenger. Every soul can reach omniscience by its own effort, and living Jinas such as Simandhara teach even now in Mahavideha.
The response
Jains came to hold that, after Mahavira's disciple Jambu, no one in this part of the world reaches omniscience in this age. In Jain belief, living Jinas teach only in distant regions, and a Jain may hope to be reborn there. So every Jain living here depends on the teaching handed down, and both traditions say those books are partly lost. The Qur'an is in anyone's hands today, and God (﷾) guards it (15:9).
Where it lands — No Jain here hears a living Jina or sees the whole truth unaided. The Qur'an can be read today, and its source is the One who knows all things.
Jaini, The Jaina Path of Purification (1979), pp. 93-94
Jaini writes that, in condemning other schools as one-sided, the Jain does not say their views are totally wrong. They are valid when seen as nayas, partial expressions of truth, and become false only when held to have absolute and exclusive validity (p. 93). His note quotes, in Sanskrit, the Svetambara Mallisena's commentary on verse 28 of Hemacandra's Anyayogavyavacchedika. Its words say that "it exists" (sat) is a naya, while "it only exists" (sad eva) is a durnaya, a faulty naya, which sets aside the thing's other properties (p. 93, n. 8). Syadvada qualifies a statement with syat, best rendered "in some respect", and eva, "in fact" (p. 94).
Cited for
Every view is partly true, so every religion holds part of the truth. No one needs to choose between them.
The response
Jain teachers do say that rival views hold part of the truth, as partial views. But they call each one false when it is held as the whole truth. They used the teaching to show that rival systems were one-sided, and they held their own path superior. The slogan also defeats itself: if every view is only partly true, so is that one.
Where it lands — Jain logic judges every view against the whole truth. It does not make every religion right.
Dundas, The Jains (2002), chapter 8, The doctrine of manypointedness
Dundas writes that, in modern times, many Jains have come to read manypointedness as an extension of non-violence to tolerance of other people's opinions. He calls this a well-meant misreading of a doctrine that was not intended to promote a universal religious tolerance. He notes that Indian religions were highly critical of their rivals' systems. The Digambara scholar Todarmal (eighteenth century) held that no one from another religious tradition could reach the correct attitude (samyaktva) needed for liberation. Jainism's consistent stance, Dundas writes, is that it is at the most profound level different from and superior to other paths.
Cited for
Anekantavada teaches humility and tolerance. Islam claims to hold the only truth, so Islam is intolerant.
The response
Claiming the truth is not the same as forcing it. The Qur'an says, "Let there be no compulsion in religion" (2:256). Dundas notes that classical Jain teachers held their own path to be superior to others. He also notes that reading anekantavada as tolerance of every opinion is modern.
Where it lands — Every serious teaching claims to be true. Islam makes its claim openly. Muslims may persuade, but they may not force anyone to become Muslim.
Qur'an 17:85 — Surat al-Isra (The Night Journey), verse 85
“They ask thee concerning the Spirit (of inspiration). Say: "The Spirit (cometh) by command of my Lord: of knowledge it is only a little that is communicated to you, (O men!)"”
Cited for
The Qur'an itself says people know only a little. So a Muslim's view is partial too, and cannot claim the whole truth.
The response
The Qur'an does say so. No Muslim claims to know all things. That is why a Muslim does not rest on a partial view of his own. He rests on what the One who knows all things sent down (6:59; 72:26-27). God (﷾) says He has perfected the religion (5:3), and He guards the Book (15:9).
Where it lands — No Muslim knows all things. A Muslim holds what the All-Knowing sent down, and God (﷾) says it is a religion made complete.
Perspectives
The Jina knows the whole truth
Mahavira became a Kevalin, all-knowing, and saw all things in all their states. His teaching is the sure guide for everyone who is not yet all-knowing.
Svetambara and Digambara teaching alike
Mahavira became a Kevalin, and knew and saw all conditions of all living beings in the world.
Rebuttal
The Qur'an says that none in the heavens or on earth, except God (﷾), knows what is hidden. Even the last Prophet (ﷺ) was told to say that he did not know the unseen. In Islam, knowledge of all things belongs to God (﷾) alone. A messenger knows of the unseen only what God (﷾) makes known to him.
The teaching of an all-knowing Jina is the sure guide, and only it can stand the test of reason.
Rebuttal
Then everything turns on the record of his words. Both traditions say the Purvas were lost, and the Digambaras hold that the Angas were lost too.
Anekantavada: the many aspects of reality
Every thing has countless aspects, so anyone short of omniscience sees only part of it. A partial view (naya) is valid in its own respect, and becomes false when held as the whole truth.
The Jain logicians: Siddhasena Divakara (claimed by both traditions), Hemacandra and Mallisena (Svetambara)
Every thing has countless qualities and states, so no one short of omniscience sees a thing whole.
Rebuttal
The Qur'an says people are given only a little knowledge. So no one reaches the whole truth by a view of his own. People know the truth they need only as God (﷾) makes it known, and He has made it known in His Book.
A partial view (naya) is valid in its own respect. It becomes false only when it is held as the whole truth (ekanta).
Rebuttal
So Jain logic does not make every view true as its holders hold it. It judges each view against the whole truth, which no partial view can supply.
Many aspects as tolerance
Anekantavada extends non-violence to the mind. It teaches humility and respect for other people's views, so no one religion should claim to hold the whole truth.
A modern reading held by many Jains
Anekantavada extends non-violence to other people's opinions, so no one religion should claim the whole truth.
Rebuttal
Dundas calls this reading modern; classical Jain teachers held their own path superior. Islam claims the truth openly. The Qur'an says there is no compulsion in religion, so Muslims may persuade but may not force anyone to become Muslim.
What the record shows
Jain teaching holds that the whole truth is seen only by one who knows all things. Jain logicians judge partial views against it. Jains hold that no one in this part of the world reaches omniscience in this age. The books that carry the Jina's teaching are partly lost and disputed.
Svetambara scriptures say Mahavira, once a Kevalin, knew and saw all conditions of all living beings in the world.
Jain logicians hold that a partial view becomes false when it is held as the whole truth.
Reading anekantavada as tolerance of every opinion is a modern reading.
Jains came to hold a view about Mahavira's disciple Jambu. After him, no one in this part of the world reaches omniscience in this age.
Jains hold that twenty Jinas teach now in distant regions of the world, such as Mahavideha. The best known of them is Simandhara.
Both traditions say the fourteen Purvas were lost, and the Digambaras hold that the Angas were lost as well.
The Islamic perspective
Only God (﷾) knows all things, and people know only what He wills. He makes known what He wills of His unseen to a messenger He has chosen, and He guards the Book He sent. A reader who seeks the whole truth is invited to examine the Qur'an and the life of the last Prophet (ﷺ).
Only God (﷾) knows the unseen. The Prophet (ﷺ) was told to say that he did not know it.
People grasp nothing of God's (﷾) knowledge except as He wills, and are given only a little knowledge.
God (﷾) makes known what He wills of His unseen to a messenger whom He has chosen.
The Prophet (ﷺ) did not speak from his own desire; what he conveyed was inspiration sent down to him.
God (﷾) sent the Qur'an down and promised to guard it.
The Qur'an invites its readers to examine it. It says that a book from other than God (﷾) would hold much discrepancy.
There is no compulsion in religion.