Written and collected by Zia H Shah MD, Chief Editor of the Muslim Times

Throughout history, the understanding of the heart’s function has evolved significantly. Until the 16th century, prevailing theories were largely influenced by ancient scholars, with the heart often considered the center of emotion, intellect, and vital life forces. The Greek philosopher Aristotle identified the heart as the most important organ of the body, the first to form according to his observations of chick embryos. He described it as a three-chambered organ that was the center of vitality in the body.

The Heart or the Qalb in the Quran

The Quran frequently references the heart (Arabic: qalb) to denote the center of human cognition, emotion, and spirituality. The term “qalb” appears approximately 132 times in the Quran, underscoring its significance in Islamic thought. quranproject.org

The Heart as a Center of Understanding:

The Quran emphasizes the heart’s role in comprehension and reflection. For instance, in Surah Al-Hajj (22:46), it states:

“Have they not traveled through the land, and do they not have hearts by which to reason and ears by which to hear? For indeed, it is not the eyes that are blinded, but blinded are the hearts within the breasts.”

This verse highlights that true blindness pertains to the heart’s inability to grasp truth, rather than mere physical sight. And here the addition that heart is within the breasts or the chest, leaves not even a shadow of doubt that we are talking about the physical heart.

The Heart’s Susceptibility to Spiritual Ailments:

The Quran also addresses the concept of hearts being sealed or diseased due to disbelief or hypocrisy. In Surah Al-Baqarah (2:7), it mentions:

“Allah has set a seal upon their hearts and upon their hearing, and over their vision is a veil. And for them is a great punishment.”

Such descriptions underscore the belief that spiritual maladies can impede one’s ability to perceive and accept divine guidance.

The Heart as the Seat of Faith and Tranquility:

Conversely, a heart receptive to faith is portrayed as being at peace. Surah Ar-Ra’d (13:28) states:

“Those who have believed and whose hearts are assured by the remembrance of Allah. Unquestionably, by the remembrance of Allah hearts are assured.”

This verse emphasizes the tranquility that faith and the remembrance of Allah can instill in the heart.

The Heart’s Role in Moral Responsibility:

The Quran associates the heart with intention and moral accountability. In Surah Al-Baqarah (2:225), it is mentioned:

“Allah does not impose blame upon you for what is unintentional in your oaths, but He imposes blame upon you for what your hearts have earned. And Allah is Forgiving and Forbearing.”

This highlights that accountability is linked to the deliberate intentions harbored within the heart.

Throughout the Quran, the heart is depicted as a multifaceted organ central to human experience. It serves as the locus of understanding, faith, intention, and moral discernment. The emphasis on the heart in the Quran underscores its pivotal role in guiding individuals towards spiritual and ethical conduct.

The very first time the word qalb is used in the Quran is in the seventh verse of Surah Baqarah, as it describes the disbelievers: “God has sealed their hearts and their hearing. Upon their eyes is a covering, and theirs is a great punishment.” In a recent multi-editor commentary by Seyyed Hossein Nasr we read about this verse:

In the Quran the heart (qalb) is the organ associated not only with the sentiment, but also with consciousness, knowledge, and faith (48:4). For example, the heart is the locus of the Divine Revelation to the Prophet (2:97); it
can be veiled to prevent understanding (6:25; 17:46), covered with rust (83:14), or hardened (2:74); it can fail to understand (7:179; 22:46), be confounded along with sight (6:110), or go blind (22:46). For other verses mentioning hearts being sealed, see 6:46; 7:100–101; 9:87, 93; 10:74; 16:108; 18:57.

Until the last few centuries, Muslim readers understood all these verses to pertain literally to the heart. Now, well-read Muslims in our times take any mention of the heart to be a metaphorical mention, realizing that, ultimately, the brain is the seat of our emotions and thoughts.

The Heart and the Modern Science

The heart, throughout history, has been revered not only as a vital organ but also as the epicenter of human emotion, intellect, and consciousness. Ancient civilizations, lacking advanced anatomical knowledge, often attributed cognitive and emotional functions to the heart. Over time, scientific exploration shifted this perspective, identifying the brain as the true seat of consciousness and the heart primarily as a circulatory pump.

Ancient Beliefs: The Heart as the Center of Being

In ancient Egypt, the heart was considered the seat of the soul and the origin of all bodily channels, including arteries, veins, and nerves. During mummification, the heart was preserved within the body due to its perceived role in the afterlife, where it would be weighed against a feather to determine the deceased’s fate. en.wikipedia.org

Similarly, ancient Greek philosophers held the heart in high esteem. Aristotle, in the 4th century BCE, proposed the cardiocentric hypothesis, asserting that the heart was the center of sensation and movement. He observed that certain animals could function without a brain but not without a heart, leading him to conclude that the heart was the primary organ of consciousness. en.wikipedia.org

Challenging the Cardiocentric View

The cardiocentric model faced challenges from proponents of the cephalocentric hypothesis, who argued that the brain was the center of thought and sensation. Galen of Pergamon, a prominent physician in the 2nd century CE, provided evidence supporting the brain’s role in controlling the body, noting that nerves originated from the brain and spinal cord. Despite this, the belief in the heart as the seat of consciousness persisted for centuries. en.wikipedia.org

William Harvey and the Circulation of Blood

A pivotal shift occurred in the 17th century with the work of English physician William Harvey. In 1628, Harvey published “Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus” (“An Anatomical Exercise on the Motion of the Heart and Blood in Living Beings”), where he detailed the mechanics of blood circulation. Through meticulous experimentation, Harvey demonstrated that the heart functioned as a pump, propelling blood through a closed circulatory system. He wrote, “The heart’s one role is the transmission of the blood and its propulsion, by means of the arteries, to the extremities everywhere.” web.stanford.edu

Harvey’s findings challenged long-held beliefs, providing a mechanistic understanding of the heart’s function and diminishing its association with consciousness. This work laid the foundation for modern physiology and underscored the importance of empirical evidence in scientific inquiry.

The Brain Takes Center Stage

Following Harvey’s discoveries, the scientific community increasingly recognized the brain as the locus of thought, emotion, and consciousness. Advancements in neuroanatomy and neurophysiology further elucidated the brain’s complex functions, solidifying its role as the center of the nervous system. The heart, while still symbolically linked to emotions in cultural contexts, was understood to be primarily responsible for blood circulation.

Epilogue

The journey from viewing the heart as the seat of consciousness to understanding its true physiological role reflects the evolution of scientific thought. Through observation, experimentation, and a willingness to challenge established beliefs, humanity has deepened its comprehension of the body’s intricate systems, distinguishing the symbolic heart from its biological function.

The qalb is perceived as the core of human consciousness and spirituality. Etymologically, “qalb” derives from a root meaning “to turn” or “to change,” reflecting the heart’s dynamic nature in Islamic thought. It is considered the seat of intellect, emotion, and intention. The Quran frequently references the qalb in contexts that emphasize its role in comprehension and guidance. For instance, Surah Al-Hajj (22:46) states:

“Have they not traveled through the land, and do they not have hearts by which to reason…?”

This verse underscores the belief that true understanding transcends mere sensory perception, residing within the heart’s reflective capacity.

Medieval scholars, such as Imam Al-Ghazali, elaborated on the qalb’s significance, viewing it as the locus of divine illumination and moral discernment. In his seminal work, “Iḥyāʾ ʿUlūm al-Dīn” (The Revival of the Religious Sciences), Al-Ghazali discusses the purification of the heart as essential for attaining spiritual proximity to God.

The purification of the qalb is central to this journey. Scholars emphasize practices such as dhikr (remembrance of God), contemplation, and adherence to ethical conduct as means to cleanse the heart of spiritual maladies like arrogance, envy, and heedlessness. A purified heart becomes receptive to divine wisdom and is capable of true understanding and sincere worship.

In summary, traditional and medieval Muslim commentators regard the qalb as the epicenter of spiritual and intellectual life. When they thought of this epicenter in terms of the human body, they thought of the heart. The moral and spiritual implications remain the same for the modern reader, but as he or she projects the thoughts to the human body, it comes out to be the brain literally and the heart metaphorically.

So, all these 132 verses about qalb now trigger somewhat different thoughts in the minds of the readers, be they devout or skeptical, and are interpreted in the light of William Harvey’s and others’ scientific discoveries.