Henry was born at Grantham and was schooled at The King's School, Grantham. Both his parents were Calvinists but he himself "could never swallow that hard doctrine." In 1631 he entered Christ's College, Cambridge, at about the time John Milton was leaving it. He took his BA in 1635, his MA in 1639, and immediately afterwards became a fellow of his college, turning down all other positions that were offered. He would not accept the mastership of his college, to which, it is understood, he would have been preferred in 1654, when Ralph Cudworth was appointed. In 1675, he finally accepted a prebend in Gloucester Cathedral, but only to resign it in favour of his friend Dr. Edward Fowler, afterwards bishop of Gloucester.
More taught many notable pupils, including Anne Finch, sister of Heneage Finch, subsequently Earl of Nottingham. She later became Lady Conway, and at her country seat at Ragley in Warwickshire, More would spend "a considerable part of his time." She and her husband both appreciated him, and amidst the woods of this retreat he wrote several of his books. The spiritual enthusiasm of Lady Conway was a considerable factor in some of More's speculations, even though she at length joined the Quakers. She became the friend not only of More and William Penn, but of Franciscus Mercurius van Helmont (1614–1699) and Valentine Greatrakes, mystical thaumaturgists of the 17th century. Ragley became a centre of devotion and spiritualism.
He devoted himself to the study of philosophy, and for a time adopted a scepticism, from which he was turned by the study of the "Platonic writers." He was fascinated especially by Neoplatonism, and this fascination never left him. The Theologia Germanica also exerted a permanent influence over him.
Spissitude is a term coined by Henry More, who used it to describe a fourth spatial dimension in which he believed the spiritual realm extended. The term refers to a measurement of an object's length along a direction in the fourth spatial dimension, analogous to the three-dimensional terms length, breadth, and height. Just as the cardinal directions in three dimensions are referred to by the terms up/down, north/south, and east/west, direction in spissitude is described by the terms ana/kata, coined by Charles Howard Hinton.
Henry More represents the mystical and theosophic side of the Cambridge movement. The Neoplatonic extravagances which lay hidden in the school from the first came to a head in his writings. He was a spiritual genius and a significant figure in British philosophy, less robust and in some respects less learned than Cudworth, but more fertile in thought. He describes himself as gifted with a buoyant temper. His own thoughts were to him a never-ending source of pleasurable excitement. He was known for his humility and charity as well as for his piety. The last ten years of his life were uneventful. He was buried in the chapel of the college he loved.
He was a prolific writer of verse and prose. The Divine Dialogues (1688), a treatise which condenses his general view of philosophy and religion. Like many others he began as a poet and ended as a prose writer. His first work, published in 1642, but written two years earlier, was entitled Psychozoia Platonica: or, a Platonicall Song of the Soul, consisting of foure severall Poems. This was followed in 1647 by his full collection of Philosophicall Poems, which includes The Song of the Soul,' much enlarged, and is dedicated ' to his dear father.' A second edition was published in the same year, and it was included by A. B. Grosart in his Chertsey Worthies Library (1878).
His prose works are :
More is also believed to have written Philosophiae Teutonicae Censura, 1670, a criticism of the theosophy of Jacob Boehme; and to have edited Joseph Glanvill's Saducismus Triumphatus, 1681. He certainlycontributed largely to the volume, and also wrote many of the annotations to Glanvill's Lux Orientalis,' 1682. More agreed with Glanvill on belief in witchcraft and apparitions. Several letters from More to John Worthington are printed in Worthington's Diary, and some Letters Philosophical and Moral between John Norris and Henry More are added to Norris's Theory and Regulation of Love, 1688. A Collection of several Philosophical Writings of Dr. Henry More includes his Antidote against Atheism, with the Appendix, Enthusiasmus Triumphatus, Letters to Des Cartes, &c., Immortality of the Soul, and Conjectura Cabbalistica. A fourth edition, 'corrected and much enlarged,' was put forth in 1712, and was 'enriched with all the Scholia or Notes that he added afterwards in his Latin edition of these works.'
More issued complete editions of his works, his Opera theologica in 1675, and his Opera philosophica in 1678. Between 1672 and 1675 More was principally engaged in translating his English works into Latin. In 1675 appeared Henrici Mori Cantabrigiensis Opera Theologica, Anglice quidem primitius scripta, mine vero per autorem Latine reddita. Hisce novus praefixus est De Synchronismis Apocalypticis Tractatulus. This was followed in 1679 by a larger work in two volumes, Henrici Mori Cantabrigiensis Opera Omnia, tum quae Latine tum quae Anglice scripta sunt; nunc vero Latinitate donata instigatu et impensis generosissimi juvenis Johannis Cockshutt nobilis Angli. Mr. Cockshutt of the Inner Temple had left a legacy of £300 to More to have three of his principal pieces translated into Latin, and More complied with the terms of the legacy by translating into Latin many more of his English works. In 1692 were published Discourses on Several Texts of Scripture, with a preface signed 'John Worthington; ' and in 1694 Letters on Several Subjects, published by Edmund Elys. Abridgments of and extracts from the works of More were numerous; and in 1708 a volume was published for charitable libraries, The Theological Works of the most Pious and Learned Henry More. The work is in English, but 'according to the author's Improvements in his Latin edition.'
The chief authorities for his life are Richard Ward's Life (1710); the prefatio generalissima prefixed to his Opera omnia (1679); and also a general account of the manner and scope of his writings in an Apology published in 1664. The collection of his Philosophical Poems (1647), in which he has "compared his chief speculations and experiences," should also be consulted. An elaborate analysis of his life and works is given in John Tulloch's Rational Theology, vol. ii. (1874); see also R Zimmermann, Henry More und die vierte Dimension des Raums (Vienna, 1881); Henry More: Tercentenary Studies, ed. by Sarah Hutton (Dordrecht, 1990).