An Integrated Model of Human Inner Experience: Nafs, Qalb, and Neuroscience

بِسۡمِ ٱللَّهِ ٱلرَّحۡمَـٰنِ ٱلرَّحِيمِ

25/04/2026

Allah knows best, but we gain knowledge through research and learning. We may be right or wrong, but we try our best. If we are wrong, we ask Allah’s forgiveness, and if we are right, then Alhamdulilah (Praise be to Allah).

Abstract

This article presents an integrated model of human inner experience by bringing together the Islamic concepts of

1-nafs (self) and

2-Qalb, Fuad and Sudur (heart), with insights from modern neuroscience.

While the Qur’an discusses the nafs and the heart in distinct contexts, their relationship can be understood through a conceptual integration in which the state of the nafs influences the condition and receptivity of the heart. By aligning these spiritual stages with patterns of cognition, emotional regulation, and behavior, this work offers a unified framework that bridges spiritual psychology and scientific understanding—without reducing one to the other.

First Opinion-Sheikh Shaarawi Opinion on Qalb, Fuad and Sudur.

Based on the linguistic and thematic interpretations often discussed by scholars like Sheikh Shaarawi, there are subtle distinctions between qalb (قلب), fu’ād (فؤاد), and sudūr (صدور) when referring to the emotional/spiritual heart in Arabic, particularly in the Quran

Here is the breakdown of the differences:

1. Qalb (قلب) – The Physical & Spiritual Core

Definition: Literal heart (the muscle), but often used to represent the core of a person, intellect, or spiritual center.
Context: It is the seat of faith, doubt, and understanding. It can be “hard,” “soft,” “locked,” or “guided.”
Use Case: Represents the foundational essence of a person’s faith or emotional state.

2. Fu’ād (فؤاد) – The Emotional Heart

Definition: A more intense or deeper heart than qalb. It refers to the heart in the context of intense emotions, feelings, and deep reflection.
Context: Used when describing deep sorrow, burning desire, fear, or profound love.
Use Case: Often associated with the heart that “sees” or perceives spiritual truths.

3. Sudūr (صدور) – Chests/Breasts

Definition: Plural of sadr (chest). It refers to the area containing the heart.
Context: Often used in the context of what is hidden or kept secret within oneself (“what is in their chests”).
Use Case: It is the vessel that holds both the qalb and the fu’ād.

Summary Table

Term	Focus	Nuance
Qalb (قلب)	Core/Faith	The essence, intellect, and seat of belief.
Fu’ād (فؤاد)	Emotion/Passion	The heart that burns with feeling, love, or sadness.
Sudūr (صدور)	Hiding Place	The chest/inner self holding secrets or intentions.

Note: While Sheikh Shaarawi often delves into these nuances, the examples provided above are common, widely accepted linguistic interpretations.

Second Opinion-Dr. Fadel Saleh Al-Samarrai Opinion on Qalb, Fuad and Sudur.

Based on the Quranic analysis of Dr. Fadel Saleh Al-Samarrai, there are distinct nuances between Sadr (صَدْر/صُدُورِ), Fu’ad (فُؤَادَ), and Qalb (قَلْبِ/قُلُوبِ).

Here is a breakdown of the differences according to his linguistic analysis of the Qur’an:

Sadr (صَدْر – Chest/Breast)
Definition: The outer layer, the chest cavity, or the “lobby” of the heart.
Function: It is the place where whispers (waswasa) occur, and where secrets are held before they are firmly settled in the heart.
Qur’anic Context: Often used when describing emotions that appear on the surface or thoughts that are not yet firmly rooted.
Example: “What is in their sudur (chests)” often refers to hidden feelings or grudges.
Qalb (قَلْب – Heart)
Definition: The core, the center, and the seat of intellect, faith, and knowledge.
Function: It is deeper than the Sadr. It is where faith, disbelief, understanding, and fear of Allah truly settle.
Qur’anic Context: Used in contexts of profound belief or disbelief. It is called “Qalb” because it flips and changes frequently (taqallub).
Fu’ad (فُؤَاد – Heart/Deep Inner Heart)
Definition: The deepest, most sensitive, and emotional part of the heart.
Function: It is often associated with intense emotions, deep contemplation, and sight (insight).
Distinction from Qalb: While Qalb is the center of faith/intellect, Fu’ad is typically linked to the profound emotional reaction or the inner perception (e.g., “The fu’ad did not lie about what it saw”).

Summary of Differences
Term Context Function
Sadr The Outer Chest The area of whispering, feelings, and hidden emotions.
Qalb The Heart/Core The seat of belief, understanding, and knowledge.
Fu’ad The Inner Heart The place of intense emotion, profound insight, and vision.

Visualizing the Order (Outer to Inner)
Sadr (Chest)—->Qalb (Heart)—–>Fu’ad (Inner Heart).

This analysis is based on the linguistic and Qur’anic expressions taught by Dr. Fadel Saleh Al-Samarrai.

Comments

As you will read on this article that science believe that the brain describes mechanisms of thought, emotion, and behavior.

My belief is that there may be specialized cells in our heart that perform the other important functions like belief, understanding, knowledge, intense emotion, profound insight, and vision. These special cells are inside the section known as Fuad and are found within the Physical Qalb, which is located inside the Sadr. Allah Knows Best.

It’s fascinating to consider this concept as akin to a small brain or brains residing within the heart, operating similarly to how the head brain does. While the Quran has not provided explicit details regarding the location of the Fuad, it does emphasize various functions and their significance in our spiritual and emotional lives.

As scientific research progresses, we may anticipate the potential discovery of additional functions that our Qalb and Fuad could fulfill in the future, further informing our understanding of this profound connection between mind and heart.

This research endeavors to compile and analyze information surrounding this intriguing subject, and if we remain alive to witness any future discoveries, we will ensure our research updates reflect those results accurately.

However, it is crucial to acknowledge that, at this moment, it is still too early to draw definitive conclusions or make any claims that may prove to be incorrect, as this topic is exceedingly complex and layered with nuances that demand careful consideration and exploration.

In our daily lives, people use the word “Qalb” to mean Heart, a term that carries immense significance in various contexts.

Besides Qalb, the Quran also mentions “Fuad” and “Sadr,” each providing a different view of the heart’s importance in our lives. While Qalb typically means the physical heart, Fuad represents additional functions related to our mind, and “Sadr” refers to the chest area that protects the Qalb and Fuad.

Together, these terms enrich our understanding of the human experience, illustrating the multifaceted nature of our inner selves and the profound influence of our hearts on our thoughts and actions.

1. Introduction

Understanding the inner human experience has been a central concern in both Islamic thought and modern science. In Islamic tradition, the human being is described through concepts such as the nafs (self), the qalb (heart), and the rūḥ (spirit). Among these, the nafs and qalb play a central role in moral struggle, perception, and transformation.

Modern neuroscience, on the other hand, explains human behavior through brain processes, emotional regulation, and cognitive systems. While these approaches differ in language and scope, they both describe aspects of the same human reality.

This article proposes that the stages of the nafs and the conditions of the heart can be meaningfully aligned with scientific patterns of cognition and emotion, forming a coherent and integrated model of the human inner system.

2. Conceptual Framework

In Islamic thought:

The nafs represents the self that inclines toward desire or discipline
The qalb represents the inner faculty of awareness, intention, and moral perception
The rūḥ represents the divine life principle, constant and pure

The relationship between these can be understood as follows:

The nafs drives behavior, the qalb perceives and decides, and the rūḥ provides the higher orientation toward truth.

From a scientific perspective:

The brain processes thoughts and emotions
The nervous system regulates bodily states
Behavior emerges from interaction between impulse and control

This article does not equate these systems directly but treats them as parallel explanatory frameworks.

3. The 7 Integrated Stages of Nafs and Heart

3.1 an-Nafs al-Ammārah (The Commanding Self)

→ Sealed / Blind Heart

Quran: 12:53;

۞ وَمَآ أُبَرِّئُ نَفۡسِىٓ‌ۚ إِنَّ ٱلنَّفۡسَ لَأَمَّارَةُۢ بِٱلسُّوٓءِ إِلَّا مَا رَحِمَ رَبِّىٓ‌ۚ إِنَّ رَبِّى غَفُورٌ۬ رَّحِيمٌ۬ (٥٣)

Quran: 2:7;

خَتَمَ ٱللَّهُ عَلَىٰ قُلُوبِهِمۡ وَعَلَىٰ سَمۡعِهِمۡ‌ۖ وَعَلَىٰٓ أَبۡصَـٰرِهِمۡ غِشَـٰوَةٌ۬‌ۖ وَلَهُمۡ عَذَابٌ عَظِيمٌ۬ (٧)

Quran: 22:46

أَفَلَمۡ يَسِيرُواْ فِى ٱلۡأَرۡضِ فَتَكُونَ لَهُمۡ قُلُوبٌ۬ يَعۡقِلُونَ بِہَآ أَوۡ ءَاذَانٌ۬ يَسۡمَعُونَ بِہَا‌ۖ فَإِنَّہَا لَا تَعۡمَى ٱلۡأَبۡصَـٰرُ وَلَـٰكِن تَعۡمَى ٱلۡقُلُوبُ ٱلَّتِى فِى ٱلصُّدُورِ (٤٦)

At this level, the individual is dominated by desires, and truth is ignored or not perceived. The heart is overpowered and unable to respond to guidance.

From a scientific perspective, this state reflects dominance of reward-driven behavior, with reduced executive control and high impulsivity. The individual is guided primarily by immediate gratification rather than reflective awareness.

3.2 an-Nafs al-Lawwāmah (The Reproaching Self)

→ Diseased Heart

Quran: 75:2;

وَلَآ أُقۡسِمُ بِٱلنَّفۡسِ ٱللَّوَّامَةِ (٢)

Quran: 2:10

فِى قُلُوبِهِم مَّرَضٌ۬ فَزَادَهُمُ ٱللَّهُ مَرَضً۬ا‌ۖ وَلَهُمۡ عَذَابٌ أَلِيمُۢ بِمَا كَانُواْ يَكۡذِبُونَ (١٠)

Here, the individual experiences guilt and internal conflict. There is awareness of wrongdoing, but inconsistency in behavior remains.

Scientifically, this corresponds to cognitive dissonance and heightened stress responses. Emotional tension arises from the conflict between impulse and moral awareness.

3.3 an-Nafs al-Mulhima (The Inspired Self)

→ Awakening / Softening Heart

Quran: 91:7–8;

وَنَفۡسٍ۬ وَمَا سَوَّٮٰهَا (٧) فَأَلۡهَمَهَا فُجُورَهَا وَتَقۡوَٮٰهَا (٨)

Quran: 39:23

ٱللَّهُ نَزَّلَ أَحۡسَنَ ٱلۡحَدِيثِ كِتَـٰبً۬ا مُّتَشَـٰبِهً۬ا مَّثَانِىَ تَقۡشَعِرُّ مِنۡهُ جُلُودُ ٱلَّذِينَ يَخۡشَوۡنَ رَبَّہُمۡ ثُمَّ تَلِينُ جُلُودُهُمۡ وَقُلُوبُهُمۡ إِلَىٰ ذِكۡرِ ٱللَّهِ‌ۚ ذَٲلِكَ هُدَى ٱللَّهِ يَہۡدِى بِهِۦ مَن يَشَآءُ‌ۚ وَمَن يُضۡلِلِ ٱللَّهُ فَمَا لَهُ ۥ مِنۡ هَادٍ (٢٣)

At this stage, the individual begins to recognize truth more clearly, and inspiration toward good actions emerges. The heart begins to soften and respond.

This aligns with increased self-awareness, reflective thinking, and early stages of behavioral change, supported by developing executive function and neuroplasticity.

3.4 an-Nafs al-Muṭmaʾinnah (The Tranquil Self)

→ Tranquil Heart

Quran: 89:27–28;

يَـٰٓأَيَّتُہَا ٱلنَّفۡسُ ٱلۡمُطۡمَٮِٕنَّةُ (٢٧) ٱرۡجِعِىٓ إِلَىٰ رَبِّكِ رَاضِيَةً۬ مَّرۡضِيَّةً۬ (٢٨)

Quran: 13:28

ٱلَّذِينَ ءَامَنُواْ وَتَطۡمَٮِٕنُّ قُلُوبُهُم بِذِكۡرِ ٱللَّهِ‌ۗ أَلَا بِذِڪۡرِ ٱللَّهِ تَطۡمَٮِٕنُّ ٱلۡقُلُوبُ (٢٨)

The individual experiences inner peace and stability, with strong trust and reliance. Emotional disturbances are significantly reduced.

Scientifically, this reflects balanced autonomic regulation, reduced stress responses, and stable emotional control, often associated with parasympathetic activation.

3.5 an-Nafs ar-Rāḍiyah (The Pleased Self)

→ Content Heart

Quran: 89:27-28;

يَـٰٓأَيَّتُہَا ٱلنَّفۡسُ ٱلۡمُطۡمَٮِٕنَّةُ (٢٧) ٱرۡجِعِىٓ إِلَىٰ رَبِّكِ رَاضِيَةً۬ مَّرۡضِيَّةً۬ (٢٨)

Quran: 57:23

لِّكَيۡلَا تَأۡسَوۡاْ عَلَىٰ مَا فَاتَكُمۡ وَلَا تَفۡرَحُواْ بِمَآ ءَاتَٮٰڪُمۡ‌ۗ وَٱللَّهُ لَا يُحِبُّ كُلَّ مُخۡتَالٍ۬ فَخُورٍ (٢٣)

So that you would not grieve over what you have lost nor become too happy about what God has granted to you. God does not love the arrogant boastful ones who are niggardly and who try to make other people also niggardly

At this level, the individual is content with life’s circumstances and shows deep acceptance of reality.

This corresponds to psychological resilience and acceptance-based cognition, where emotional reactivity is low and stability is high.

3.6 an-Nafs al-Marḍiyyah (The Pleasing Self)

→ Sound Heart (Developing)

Quran: 89:28;

ٱرۡجِعِىٓ إِلَىٰ رَبِّكِ رَاضِيَةً۬ مَّرۡضِيَّةً۬ (٢٨)

Quran: 26:89

إِلَّا مَنۡ أَتَى ٱللَّهَ بِقَلۡبٍ۬ سَلِيمٍ۬ (٨٩)

The individual consistently acts with sincerity and becomes pleasing in character and behavior. The heart is purified and stable.

Scientifically, this aligns with prosocial behavior, empathy, and consistent moral decision-making, reflecting strong integration of values and actions.

3.7 an-Nafs al-Kāmilah (The Complete Self)

→ Fully Sound Heart (Qalb Salīm)

Quran: 26:89;

إِلَّا مَنۡ أَتَى ٱللَّهَ بِقَلۡبٍ۬ سَلِيمٍ۬ (٨٩)

Quran: 91:9–10

قَدۡ أَفۡلَحَ مَن زَكَّٮٰهَا (٩) وَقَدۡ خَابَ مَن دَسَّٮٰهَا (١٠)

At the highest level, the individual achieves full sincerity, clarity, and alignment. There is no inner contradiction.

This reflects a state of full psychological integration, where cognition, emotion, and behavior operate in harmony.

4. Integrating Spiritual and Scientific Perspectives

The stages described above represent a progression from impulsive, desire-driven behavior to complete inner harmony and alignment. While Islamic teachings describe this journey in moral and spiritual terms, neuroscience provides insight into how these states are experienced through patterns of cognition, emotion, and neural regulation.

It is important to emphasize that these correspondences are not direct equivalences. Rather, they represent functional parallels, where spiritual states are reflected in observable psychological and biological patterns.

5. The Heart–Brain Connection: Contemporary Scientific Insights

The integration of the concepts of nafs and qalb with modern scientific understanding offers a rich and comprehensive model of the human inner experience. This model demonstrates that spiritual growth and psychological development are deeply interconnected, even when described through different frameworks.

Ultimately, the journey of the human being can be understood as a movement from being controlled by desire to becoming guided by truth, culminating in a state of inner harmony where the self, the heart, and behavior are fully aligned.

Recent advances in neurocardiology have revealed that the human heart is more than a simple mechanical pump. It possesses an intrinsic cardiac nervous system (ICNS), sometimes referred to as the “little brain in the heart,” consisting of approximately 40,000 neurons embedded within the heart.

This system is capable of semi-autonomous regulation of cardiac function, including heart rhythm and responsiveness to physiological changes. It can detect pressure and chemical signals, and it communicates continuously with the brain through neural, biochemical, and electromagnetic pathways. These interactions contribute to the regulation of emotional and stress-related bodily responses.

These findings are significant. They show that the heart is an active and dynamic participant in human physiological and emotional experience. This supports a broader understanding of the human inner system as deeply interconnected, where bodily states, emotional responses, and cognitive processes continuously influence one another.

In light of this, the Qur’anic concept of the Qalb can be appreciated with greater depth. While the qalb is not reducible to the physical heart or its neural network, the centrality of the heart in human experience—as both felt and lived—resonates with the Qur’anic emphasis on the heart as the locus of inner awareness, transformation, and receptivity.

Thus, contemporary science does not “prove” the spiritual concept of the qalb, but it enriches our understanding of why the heart holds such a central place in human language, experience, and spiritual reflection.

These insights further support an integrated model in which the nafs, qalb, and bodily systems interact dynamically, reflecting both spiritual and physiological dimensions of the human being.

In the Qur’anic framework, the Fuad is defined not by its physical location but by its function: it is the inner faculty of understanding, perception, belief, and moral response. It can be open or sealed, healthy or diseased, and its state determines a person’s receptivity to truth and guidance.

6. The Location of the Fuad: Between Experience and Reality

While the Qur’an does not define the Fuad in anatomical terms, it is often associated with the region of the Sadr and Qalb (The physical heart) in both language and human experience.

This association reflects how people naturally experience emotions such as fear, love, and anxiety—as sensations centered in the chest.

From this perspective, it is reasonable to say that the Fuad is “at the Qalb (heart) in an experiential and symbolic sense. However, this should not be understood as a strict physical identification. The Fuad, as described in the Qur’an, functions as a non-material faculty of understanding, intention, and spiritual perception. It is connected to the human body—expressed through physiological and neurological processes. Its effects are reflected in human awareness, behavior, and inner transformation.

7. Language vs Qur’anic Terminology (Nafs, Qalb, Rūḥ)

In everyday language, people more commonly describe individuals as having a ‘good’ or ‘bad rūḥ,’ while expressions involving the heart are typically framed in terms of kindness (‘good heart’) or emotional hardness (‘cold-hearted’). In Islamic terminology, however, moral qualities are more precisely attributed to the nafs and the state of the qalb, whereas rūḥ refers to a divinely originated aspect of life that is not described in moral terms.

In everyday speech, terms like “heart” and “rūḥ” are used loosely to describe personality and emotional qualities. However, in the Qur’anic framework, moral and spiritual states are more precisely associated with the nafs (self) and the qalb (heart), while the rūḥ is understood as a pure, divinely-originated essence that is not described in terms of moral corruption or goodness.

Everyday Language	What People Usually Mean	Qur’anic / Islamic Term (Precise)	Meaning in Islamic Framework
“Good person”	Kind, moral, well-behaved	Nafs al-Muṭmaʾinnah / Qalb Salīm	A purified self and sound heart aligned with truth
“Bad person”	Harmful, immoral, selfish	Nafs al-Ammārah / Diseased Qalb	A self dominated by desire and a heart blocked from truth
“Good heart”	Kind, compassionate nature	Qalb Salīm (sound heart)	A heart purified from arrogance, envy, and corruption
“Bad heart”	Cold, cruel, emotionally hard	Qalb Marīḍ / Qalb Qāsī (diseased or hardened heart)	A heart that is spiritually insensitive or resistant to truth
“Good rūḥ”	Positive energy, pleasant personality	Not a Qur’anic moral category	Rūḥ is pure by origin and not described as good/bad
“Bad rūḥ”	Negative presence, bad vibe	Not a Qur’anic moral category	Rūḥ is not morally corrupted in Islamic teaching
“Inner self”	Feelings, identity, personality	Nafs + Qalb (combined experience)	The self and heart together form moral awareness and behavior

Functions of the Brain (Scientific View)

The brain works as a network of specialized regions, each contributing to different functions:

1. Prefrontal Cortex (PFC)

Reasoning and decision-making
Self-control and impulse regulation
Planning and long-term thinking
Moral judgment (executive control)

“Control center” for rational behavior

2. Limbic System (Emotional Brain)

Includes: amygdala, hippocampus

Emotional reactions (fear, anger, pleasure)
Emotional memory
Stress response
Attachment and bonding

“Emotion generation and emotional memory system”

3. Amygdala

Fear detection
Threat response
Emotional intensity (especially fear/anger)

“Alarm system of the brain”

4. Hippocampus

Memory formation
Learning and recall
Contextual understanding

“Memory indexing system”

5. Basal Ganglia

Habit formation
Reward-based learning
Automatic behaviors

“Habit and repetition system”

6. Hypothalamus

Hormonal regulation
Hunger, thirst, sleep
Emotional-body connection

“Body regulation center”

Functional Dimensions of the Qalb (Qur’anic Framework)

The Qur’an does not divide the qalb into physical parts. Instead, it describes functional states and abilities:

1. Qalb as Understanding (Tafaqquh)

“They have hearts with which they do not understand…” (7:179)

Deep comprehension of truth
Reflection and insight
Moral awareness

Function: inner understanding beyond information

2. Qalb as Perception (Basīrah)

“Not the eyes are blind, but the hearts…” (22:46)

Inner vision
Recognizing truth vs falsehood
Spiritual awareness

Function: perceiving meaning and reality

3. Qalb as Belief Center (Īmān / Kufr)

“Faith has been written in their hearts…” (58:22)

Acceptance or rejection of truth
Formation of belief
Conviction

Function: belief formation and certainty

4. Qalb as Intention (Niyyah)

Sincerity or hypocrisy
Direction of actions
Inner motivation

Function: moral intention system

5. Qalb as Emotional State (Taḥawwul)

Love, fear, tranquility
Hardening or softening
Stability or disturbance

Function: emotional-spiritual state regulation

6. Qalb as Changeable Center (Taqallub)

(from root meaning “to turn/change”)

Constant shifting states
Influence of actions and choices
Spiritual transformation

Function: dynamic inner transformation system

Integrated Understanding

Now we connect them correctly:

Brain=mechanism of cognition, emotion, and behavior
Qalb/Fu’ad (The Heart/Core)=The seat of belief, understanding, and knowledge. The Inner Heart The place of intense emotion, profound insight, and vision. Inner faculty of meaning, intention, and moral perception.

They interact, but are not identical.

Brain vs Qalb — Functional Comparison Chart

Brain (Scientific Functions)	Qalb/Fuad (Qur’anic Functions)
1-Prefrontal Cortex Reasoning, planning, self-control, decision-making	1-Qalb as Understanding (7:179) Deep comprehension, reflection, insight into truth
2-Limbic System Emotional generation (fear, joy, anger), emotional memory	2-Qalb as Emotional State Tranquility, fear of Allah, hardness or softness of heart
3-Amygdala Threat detection, fear response, emotional intensity	3-Qalb as Awareness of Truth (22:46) Inner perception of reality (basīrah)
4-Hippocampus Memory formation and recall	4-Qalb as Retention of Guidance Remembering, reflecting, internalizing signs
5-Basal Ganglia Habit formation, automatic behavior patterns	5-Qalb as Moral Conditioning Repeated actions shaping spiritual state
6-Hypothalamus Hormonal and body regulation (stress, hunger, sleep)	6-Qalb–Body Influence Inner state affects emotional and physical response
7-Whole Brain Network Integrates cognition, emotion, and behavior	7-Qalb as Inner Center (Taqallub) Constantly changing spiritual condition (purity, hardness, openness)

The Heart, the Qalb, and the Limits of Interpretation

The physical heart (Qalb in Arabic) is an organ that pumps blood and keeps circulation going. Modern neuroscience has found a nervous system in the heart, called a “little brain,” which can control heart activity and talk to the central nervous system. This little brain might be the Fuad mentioned in our comparison table.

In the stories about the Prophet Muhammad ﷺ, the opening of the chest and cleansing of the heart describe a miraculous event (muʿjizah). This event represents a special preparation and purification of the Prophet’s inner self. The part that was cleaned might be the Fuad mentioned earlier. Allah knows best.

Ultimately, modern scientific discoveries about the heart–brain connection improve our understanding of the human body. However, they do not negate or replace the Qur’anic idea of the Fuad. Instead, they highlight the strong connection between body and experience, while the true nature of the fuad goes beyond what we can measure and is known only to Allah. Perhaps one day, science will discover the cells of the Fuad within the Qalb.

Inshaallah (if Allah wills) More research will be done soon on this page.