Biblical Distinction Between Heart and Brain in Spiritual Life
In biblical thought, the "heart" and "mind" are often understood differently than in modern Western conceptions, with the heart frequently encompassing intellectual and volitional aspects typically associated with the brain [1, 8]. The Bible presents the heart as the central locus of a person's spiritual activity and the totality of human life [1].
While modern understanding often separates the heart as an emotional center from the brain as the seat of intellect, biblical usage is more comprehensive. The Easton's Bible Dictionary notes that the heart is the "home of the personal life," from which a person is designated as wise, pure, upright, pious, or good [1]. Passages like Deuteronomy 6:5 and Matthew 22:37 use "heart" and "soul" interchangeably in the command to love God, indicating the heart's comprehensive role in one's being [1]. Abraham Ibn Ezra, a medieval Jewish commentator, explicitly states that "the heart refers to knowledge" and is "another term for the spirit of intelligence, the rational soul," serving as its primary residence [8]. He connects this understanding to phrases like "wise-hearted" (Exodus 36:1) and "he that getteth a heart" (Proverbs 19:8), where "heart" signifies wisdom and understanding [8].
The Bible also uses "mind" (or "understanding") in conjunction with the heart, sometimes distinguishing their functions but often showing their interconnectedness. Job 38:36 asks, "Who has put wisdom in the heart or given understanding to the mind?" [3]. This verse suggests a relationship between wisdom residing in the heart and understanding being given to the mind. The apostle Paul, in Romans 8:6, contrasts "the mind of the flesh" which leads to death, with "the mind of the Spirit" which brings life and peace [2]. This implies that the "mind" can be oriented either carnally or spiritually, under the influence of different forces.
The Jamieson, Fausset & Brown Commentary on Ephesians 1:18 notes that older manuscripts and versions read "heart" where some later texts have "understanding," emphasizing that the "eyes of your heart" are enlightened [6]. This commentary describes the heart as "the core of life" and "the fountain of the thoughts," further blurring a strict modern distinction between heart and brain [6].
Some biblical texts also attribute intellectual or volitional functions to other organs. For instance, the kidneys were sometimes seen as organs of understanding, similar to how the modern world views the brain, and the liver was associated with life and vitality, akin to the modern concept of the heart [4]. Passages like Psalm 7:9 and Jeremiah 12:2 refer to the kidneys in relation to motives and thoughts [4].
Theological traditions have engaged with these biblical nuances. Charles Hodge, in his Systematic Theology, argues against a broad distinction between the understanding and the heart, asserting that the whole soul is subject to inherent corruption, not just the affections [7]. This perspective aligns with the biblical view that the heart encompasses the entire inner person, including rational faculties [7]. Thomas Aquinas, in his Summa Theologica, discusses Plato's view that different vital actions were located in distinct organs—nutritive power in the liver, concupiscible in the heart, and knowledge in the brain—but notes Aristotle's rejection of this strict separation for parts of the soul that use corporeal organs [5].
Sources
- Easton's Bible Dictionary “Easton's Bible Dictionary: Heart — According to the Bible, the heart is the centre not only of spiritual activity, but of all the operations of human life. "Heart" and "soul" are often used interchangeably (Deut. 6:5; 26:16; comp. Matt. 22:37; Mark 12:30, 33), but this is not generally the case. The heart is the "home of the personal life," and hence a man is designated, according to his heart, wise (1 Kings 3:12, etc.), pure (Ps. 24:4; Matt. 5:8, etc.), upright and righteous (Gen. 20:5, 6; Ps. 11:2; 78:72), pious and good (Luke 8:15), etc. In these and such passages the word "soul" could not ”
- Romans “Romans 8:6 (BSB) — The mind of the flesh is death, but the mind of the Spirit is life and peace,”
- Job “Job 38:36 (BSB) — Who has put wisdom in the heart or given understanding to the mind?”
- Leviticus (Protestant academic) “Tyndale House on Leviticus 3:4: 3:4 kidneys . . . lobe of the liver: The Israelites saw the kidneys as organs of understanding, much like how we think of the brain (“I am overwhelmed [literally my kidneys are consumed],” Job 19:27; “heart,” Pss 7:9; 16:7; Jer 12:2; Lam 3:13; “motives,” Ps 26:2; Jer 17:10; “thoughts,” Jer 11:20; 20:12). The liver represented life and vitality, similar to how we think of the heart (Prov 7:23; “spirit,” Lam 2:11).”
- theology (Catholic (Scholastic)) “Aquinas, Summa Theologica, First Part (Prima Pars), Of the Union of Body and Soul, Art. 3: Article: Whether besides the intellectual soul there are in man other souls essentially different from one another? I answer that, Plato held that there were several souls in one body, distinct even as to organs, to which souls he referred the different vital actions, saying that the nutritive power is in the liver, the concupiscible in the heart, and the power of knowledge in the brain. Which opinion is rejected by Aristotle (De Anima ii, 2), with regard to those parts of the soul which use corporeal or”
- Ephesians (Presbyterian) “Jamieson, Fausset & Brown on Ephesians 1:18: understanding--The oldest manuscripts, versions, and Fathers, read "heart." Compare the contrary state of unbelieving, the heart being in fault (Eph 4:18; Mat 13:15). Translate, "Having the eyes of your heart enlightened" (Eph 5:14; Mat 4:16). The first effect of the Spirit moving in the new creation, as in the original physical creation (Gen 1:3; Co2 4:6). So THEOPHILUS to AUTOLYCUS (1.3), "the ears of the heart." Where spiritual light is, there is life (Joh 1:4). The heart is "the core of life" [HARLESS], and the fountain of the thoughts; whence "”
- CCEL (Reformed (Old Princeton)) “Charles Hodge, Systematic Theology, Vol. 2, section 51: body with which the believer is hereafter to be invested. The Whole Soul the Seat of Original Sin. The theory that the affections (or, the heart in the limited sense of that word), to the exclusion of the rational faculties, are alone affected by original sin, is unscriptural, and the opposite doctrine which makes the whole soul the subject of inherent corruption, is the doctrine of the Bible, as appears, — 1. Because the Scriptures do not make the broad distinction between the understanding and the heart, which is commonly made in our ph”
- Sefaria (Jewish (Rationalist)) “Abraham Ibn Ezra on Deuteronomy 6:5: WITH ALL THY HEART, AND WITH ALL THY SOUL. The heart refers to knowledge. It is another term for the spirit of intelligence, 21 The rational soul. for the heart is its first residence. 22 See I.E. on Gen. 1:1 (Vol. 1, p. 25): “Speech is called safah (lip) because it is seen to come from the lips. Similarly, man’s highest soul is called heart ( lev )…because the heart is its first resting place.” The same applies to wise-hearted (Ex. 36:1) and to He that getteth a heart (Prov. 19:8). 23 Translated literally.”