Eyes closed, hands on face. With eyes closed, the brain changes its rhythm: the alpha rhythm increases (Hans Berger, 1929). Light pressure on the eyelids produces phosphenes, flashes of light that arise from the intrinsic activity of the visual system. Darkness is never complete: the brain perceives its own light, called in German Eigenlicht. Be gentle: pressing on the eyeball can slow the heart rate (oculocardiac reflex).

Plugged ears. Plugging the ears amplifies bodily sounds (pulse, circulation, respiration) through bone conduction. In near-total silence, many people also hear a faint buzzing, as demonstrated by experiments in an anechoic chamber (Heller and Bergman, 1953). These are probably the "psychophysiological phenomena" of early practice, which fade when attention ceases to focus on them.

Sensory deprivation. Hebb's experiments at McGill University (Bexton, Heron, and Scott, 1954) showed that reduced stimulation can elicit spontaneous imagery. This serves as a reminder that internal light and sounds can be produced by the brain itself.

Meditation and mindfulness. Imaging studies show that sustained practice reduces activity in the default mode network, associated with rumination and the feeling of a constantly talking self (Brewer et al., 2011). This aligns with the concept of a "calmed ego." However, there is no universal threshold of 1000 minutes: the effects vary depending on the individual, the methods used, and the regularity of the practice.

Limitation. Science can describe these experiences and their neural correlates. It can neither confirm nor deny that one "sees the soul" in them: that is a metaphysical question, outside its field.

Hinduism. The Katha Upanishad (II, 1, 1) states that the senses are directed outward and that the sage turns them away to see the Self. The Bhagavad Gita (VIII, 12) speaks of one who has "closed all the doors." Patanjali defines pratyahara, withdrawal of the senses (II, 54). The Chandogya Upanishad (III, 13, 7-8) associates the light of the heart with a sound perceived by closing the ears. The Nada Upanishads (including the Nada Bindu) and the Hatha Yoga Pradipika (Chapter IV) elaborate on listening to the inner sound (Shabda, Nada). Tejas signifies radiance and light. The hand gesture over the eyes, ears, nose and mouth corresponds to the Ṣaṇmukhī mudrā, practiced in the yoga tradition.

Buddhism. Guarding the gates of the senses (indriya-saṃvara) is a fundamental discipline (Dīgha Nikāya 2). In the Śūraṅgama Sūtra, Avalokiteśvara attains enlightenment by turning his listening inward. Dōgen's Zen speaks of "turning the light inward" (Fukanzazengi).

Christianity. “When you pray, go into your room and close the door” (Matthew 6:6). Catholic tradition extends this practice with Augustine, Teresa of Avila, John of the Cross, and Meister Eckhart. Orthodoxy adds hesychasm: bringing the intellect back into the heart to see the light of Tabor (Gregory Palamas).

Islam. Retreat (khalwa) and dhikr (remembrance of God) are central Sufi practices. The Quran (24:35) states that God is "light upon light"; Suhrawardi and Ibn Arabi derive from this a philosophy of illumination and the heart.

Judaism. Psalm 4:5 says: “Speak in your hearts on your beds, and be silent.” The Hasidism of Nachman of Breslov practices prayerful isolation (hitbodedut).

Taoism. “Block the orifices, close the doors” (Daodejing 52).

Sikhism. Meditation on the Nām and the Shabad; tradition speaks of an inner “tenth gate”.

Jainism. The sāmāyika and the dhyāna are times of silence where one detaches oneself from objects to discover the pure Self.

Bahá'í. Prayer and meditation are recommended, but without monasticism: the inner life is fulfilled in service to the world.

Other traditions. The silence of Quaker assemblies and the vision quests of indigenous peoples also rely on temporary withdrawal from the outside world.

This overview reveals that closing off the senses is an almost universal practice. Traditions differ on the goal: union with the divine, pure Self, emptiness, or service to the world. They also differ on the role of technology: some cultivate it, others consider it secondary.

The interior door

Throughout the course of a single day, we perform gestures that skim the surface, and others that are filled with a vibrant essence. To open the inner door, one must first close the outer doors.

This golden rule is thousands of years old. Let's replace the word "door" with the word "meaning": to awaken inner meaning, we must calm the outer senses. Eyes close, ears fall silent, and the question remains: do we see our soul when the world fades away?

The hands, which ordinarily defend us, then become the threshold. Placed on the face, they no longer protect from the world; they open us to the inner self. Two paths present themselves: listening to the subtle sound, Shabda, and contemplating the light, Tejas.

At first, the body murmurs: glimmers, buzzing, stirrings. These phenomena pass like waves on a lake that is finally left in peace. It is enough to persevere, without expecting anything, until the ego, satiated with silence, ceases to demand.

The secret is not revealed; it is experienced. Each person is invited to open for themselves, minute by minute, the door that no one else can cross in their place. And at the center lies not a conquest but a state of repose: a motionless axis around which everything else revolves.