Open Neuroscience has made great progress on how the brain works. There is no agreed scientific theory of why brain activity is accompanied by experience.
Close your eyes and taste a strawberry. Somewhere in your head, about 86 billion nerve cells are firing in patterns that scientists can increasingly measure. But none of those measurements contains the taste. The taste is yours alone. No one else can have it, and no scan has ever shown it.
In 1994 a young Australian philosopher, David Chalmers, stood up at a conference in Arizona and gave this puzzle a name: the hard problem of consciousness. Thirty years on it is still unsolved. Some think it points to a soul, some to a deeper kind of physics, and some think it is a trick our brains play on us.
“They are asking thee concerning the Spirit. Say: The Spirit is by command of my Lord, and of knowledge ye have been vouchsafed but little.”
Qur'an 17:85 · Pickthall (1930)
This verse, from the chapter al-Isra (The Night Journey), answers a question put to the Prophet Muhammad ﷺ (peace be upon him) about the ruh, the spirit. It does not explain the spirit; it says it comes from God and that human knowledge is limited. The book of Proverbs has its own image: “The spirit of man is the lamp of the LORD, searching all the inward parts” (Proverbs 20:27, JPS 1917).
What science shows
The human brain contains about 86 billion neurons, according to work by the Brazilian neuroscientist Suzana Herculano-Houzel. Brain scans can now show which areas become active when you see a face, feel pain or make a choice. Damage to particular regions changes particular abilities, and general anaesthetic switches consciousness off in minutes. Our science page on the brain tells that story.
In 1995 Chalmers drew a line between the ‘easy’ problems and the hard one. The easy problems, which are still very difficult, are about what the brain does: noticing, remembering, reporting. The hard problem is why any of that is accompanied by experience, what it is like to be you. He argued that explaining the functions would not, by itself, explain the feeling.
Scientists have proposed several theories. Global Neuronal Workspace Theory says consciousness arises when information is broadcast widely across the brain. Integrated Information Theory says it depends on how much information a system combines as a whole. In an unusual experiment, the Cogitate Consortium tested the two rival theories against each other, with predictions agreed in advance. The results, published in Nature in 2025, did not crown a winner: key predictions of both theories failed.
The field is lively and sometimes heated. In 2023, 124 researchers signed a public letter calling Integrated Information Theory pseudoscience, and others replied that the letter itself was damaging. The neuroscientist Anil Seth at the University of Sussex argues for patient work on the ‘real problem’: explaining, predicting and controlling the features of experience, one by one.
So in 2026 there is no scientific consensus on what consciousness is. That is not a gap for God to fill; it is an honest description of where research stands.
The arguments, fairly
Experience is not like anything else. Physical science describes size, shape, charge and motion. None of those, the argument goes, adds up to the taste of a strawberry. Richard Swinburne, an Oxford philosopher and Christian, argues that the soul is a real, non-physical part of a person, and that its existence is better explained by God than by chance.
Mind may be basic. If experience cannot be built from unexperiencing parts, then mind may be part of the foundation of reality. Many believers see this as fitting a world made by a conscious Creator. The philosopher Philip Goff at Durham reaches a related view, panpsychism, without belief in the God of the faiths.
The soul as its own substance. Saadia Gaon, in The Book of Beliefs and Opinions (933), argued that God creates the soul as a substance of its own, as pure as the heavenly spheres. It acts through the body without being made of it.
We know mind first. Ibn Sina’s ‘flying man’ thought experiment asks you to imagine being created in mid-air, with no senses at all. You would still know that you exist. For many, this shows that the self is known more surely than the body.
Our ignorance is not evidence. Not knowing how the brain produces experience does not show that it does not. Electricity and life were once called mysteries beyond physics.
It may be an illusion. Daniel Dennett, who died in 2024, argued that the ‘hard problem’ comes from a mistaken picture of the mind; once the brain’s functions are explained, nothing is left over. The philosopher Keith Frankish calls this view illusionism.
The brain is in charge. Brain injury, dementia, drugs and anaesthesia all change or remove consciousness. Sceptics argue that this close dependence is exactly what we would expect if the mind is what the brain does.
Where it stands
Open. No scientific theory of consciousness is agreed, and philosophers are split between physicalists, dualists, panpsychists and others. The hard problem itself is disputed: some think it is the deepest question there is; others think it will dissolve.
Believers do not all hold one view either. Some are dualists; others think the soul is not a separate thing but the life and form of the whole person.
What each faith says
Judaism
“The spirit of man is the lamp of the LORD, searching all the inward parts.”
Proverbs 20:27 · JPS 1917
In Genesis, God forms the first human from the dust and breathes into his nostrils “the breath of life” (Genesis 2:7). Jewish tradition calls the soul neshamah, from the same root as breath. Every morning observant Jews say a blessing that begins: “My God, the soul You placed within me is pure”, and thanks God for returning it after sleep (Talmud, Berakhot 60b).
Jewish thinkers have described the soul in different ways. Maimonides, following Aristotle, spoke of the intellect as what makes us human. The mystical tradition speaks of levels of soul. What they share is the conviction that a person is more than a body, and that human awareness is a lamp lit by God, able to search inward and know itself.
Christianity
“For who amongst men knows the things of a man except the spirit of the man which is in him? Even so, no one knows the things of God except God’s Spirit.”
1 Corinthians 2:11 · WEB
Christians believe humans are made in the image of God (Genesis 1:27), able to know, love and choose. Paul asked: “who amongst men knows the things of a man except the spirit of the man which is in him?” (1 Corinthians 2:11). Thomas Aquinas, following Aristotle, taught that the soul is the ‘form’ of the body, what makes it a living person, rather than a ghost inside a machine.
Christian philosophers today hold a range of views. Richard Swinburne defends a soul distinct from the body. Others, such as the theologian Nancey Murphy, argue that humans are physical beings whose minds are not separate substances, and that Christian hope rests on resurrection, not on an immortal soul. Both positions are held within the church.
Christian contemplatives explored the inner life from the inside. Julian of Norwich, the fourteenth-century anchoress, wrote of the soul as a city where God dwells. The Carmelite Teresa of Ávila pictured it as an interior castle of many rooms (1577).
Islam
“And (also) in yourselves. Can ye then not see?”
Qur'an 51:21 · Pickthall (1930)
The Qur’an says that God shaped the first human and “So, when I have made him and have breathed into him of My Spirit, do ye fall down, prostrating yourselves unto him.” (15:29, Pickthall), and it invites people to look inward: “And (also) in yourselves. Can ye then not see?” (51:21, Pickthall). It also says, in our sign verse, that knowledge of the spirit is limited. Muslim scholars have long distinguished the ruh (spirit), the nafs (self) and the qalb (heart), the seat of understanding.
Ibn Sina, around 1020, devised the ‘flying man’ to show that we know ourselves directly. Al-Ghazali opened his Persian work The Alchemy of Happiness with knowledge of the self as the key to knowing God. Today many Muslim thinkers welcome neuroscience while holding, with 17:85, that the inner life is a sign whose depths humans will never fully reach.
Without religion
Non-religious thinkers stand on every side of this debate. The philosopher Daniel Dennett, an atheist, argued that the hard problem is an illusion: explain what the brain does, and nothing is left over. Yet the philosopher Thomas Nagel, also an atheist, has argued since his 1974 essay ‘What Is It Like to Be a Bat?’ that physical science leaves experience out. In Mind and Cosmos (2012) he went further, saying a purely materialist picture of nature is probably false, without turning to God.
Most humanists expect a natural explanation, and are content to wait for it. Many say that if the mind is what the brain does, each person’s inner life is more precious, not less: it happens once, and then it is gone. That is a reason, they say, to treat every other mind with care.
Same and different
Each of the three faiths speaks of the human spirit as God’s breath or gift, and each treats self-knowledge as a path to knowing God. All three have thinkers who see the soul as separate from the body and thinkers who see it as the life of the whole person. Christianity places special weight on bodily resurrection; Judaism and Islam teach it too, with their own emphases. Many non-religious people share the sense that consciousness is the strangest thing in the universe; most expect a natural explanation.
A moment to reflect
- Could a perfect description of your brain ever include what it is like to be you?
- If a computer said it was conscious, how would you decide whether to believe it?
- Does the idea of a soul make more sense to you as a separate thing, or as the life of the whole person?
- When did you last feel amazed simply to be aware: of a taste, a sound, a face?
We end on a question
If you are more than your brain, what is the more; and if you are not, why does being you feel like anything at all?
Watch
David Chalmers explains the hard problem in his own words.
Daniel Dennett gives the opposite case: that consciousness is not what it seems.
Anil Seth at the Royal Institution on what neuroscience has learned about consciousness.
Philip Goff argues that consciousness may be a basic feature of reality.
Richard Swinburne, a Christian philosopher, on why he believes people have souls.
Do it together
In pairs, try to describe the colour red to someone who has never seen it, without naming red things. Afterwards discuss: what could you share, and what could you not?
Read Ibn Sina’s thought experiment aloud and sit quietly for two minutes imagining it. Then share: what did you still know about yourself? Compare with Descartes’ ‘I think, therefore I am’, written six centuries later.
Visit a museum or science centre with a brain exhibit, such as the Science Museum or Wellcome Collection in London. Talk afterwards about one thing science explained and one thing it left open.
Many Jews begin the day with Elohai Neshamah, ‘My God, the soul You placed within me is pure’. Read it together, then each person writes one sentence beginning ‘Thank you for…’ about something only they can feel.
Read a short passage from Teresa of Ávila’s Interior Castle and draw your own ‘castle’ of inner rooms: where do you go when you are calm, afraid, curious? Share only what you wish to.
Go deeper
- Consciousness (Stanford Encyclopedia of Philosophy) · article
- Adversarial testing of theories of consciousness (Nature, 2025) · paper
- Chalmers, Facing Up to the Problem of Consciousness (1995) · paper
- Ibn Sina on the soul (Stanford Encyclopedia of Philosophy) · article
- Qur'an 17:85 (Quran.com) · scripture
- Berakhot 60b, the morning blessing for the soul (Sefaria) · scripture
- Julian of Norwich, Revelations of Divine Love (Christian Classics Ethereal Library) · book
- Saadya [Saadiah] Gaon (Stanford Encyclopedia of Philosophy) · article
Check yourself
Three quick questions. No score, nothing saved.
1. Who named 'the hard problem of consciousness' in 1994?
2. About how many nerve cells are in the human brain?
3. Qur'an 17:85 says of the spirit (ruh)…
Sources (6)
- About 86 billion neurons: Azevedo, Herculano-Houzel et al., J. Comparative Neurology 2009 (PubMed)
- Easy and hard problems of consciousness: Chalmers, Journal of Consciousness Studies 2(3), 1995
- Cogitate adversarial collaboration: IIT and GNWT predictions both partly failed: Cogitate Consortium, Nature, 2025
- 124 scholars' letter calling IIT pseudoscience, Sept 2023: Nature news, 20 Sep 2023
- Positions: physicalism, dualism, panpsychism, illusionism: Van Gulick, Consciousness, SEP
- Ibn Sina's flying man: Arabic and Islamic Psychology and Philosophy of Mind, SEP
