Born in Manchester, the son of Samuel Greg, the creator of Quarry Bank Mill, he was brother to Robert Hyde Greg and the junior Samuel Greg. He was educated at the University of Edinburgh. For a time, he managed a mill of his father's at Bury, and in 1832 began business on his own account. He entered the struggle for free trade, and obtained in 1842 the prize offered by the Anti-Corn Law League for the best essay on Agriculture and the Corn Laws.

He was too busy with political, economical and theological speculations to give undivided attention to his business, which he gave up in 1850 to devote himself to writing. His Creed of Christendom was published in 1851, and in 1852 he contributed no less than twelve articles to fourleading quarterlies. Disraeli praised him. Sir George Cornewall Lewis bestowed a Commissionership of Customs on him in 1856. In 1864 he was made Comptroller of the Her Majesty's Stationery Office.

He became a member of the Metaphysical Society. Besides contributions to periodicals he produced several volumes of essays on political and social philosophy. The general spirit of these is indicated by the titles of two of the best known, The Enigmas of Life (1872) and Rocks Ahead (1874). They represent a reaction from the high hopes of the author's youth, when wise legislation was assumed to be a remedy for every public ill. Greg was a man of deep moral earnestness of character and was interested in many philanthropic works. He died at Wimbledon, London.

His son, Percy Greg, was also a writer.

Quotations

"This doctrine [the efficacy of prayer] has in all ages been a stumbling block to the thoughtful. It is obviously irreconcilable with all that reason and revelation teach us of the divine nature; and the inconsistency has been felt by the ablest of the Scripture writers themselves. Various and desperate have been the expedients and suppositions resorted to, in order to reconcile the conception of an immutable, all-wise, all-foreseeing God, with that of a father who is turned from his course by the prayers of his creatures. But all such efforts are, and are felt to be, hopeless failures. They involve the assertion and negation of the same proposition in one breath. The problem remains still insoluble; and we must either be content to leave it so, or we must abandon one or other of the hostile premises."

"The religious man, who believes that all events, mental as well as physical, are pre-ordered and arranged according to the decrees of infinite wisdom, and the philosopher, who knows that, by the wise and eternal laws of the universe cause and effect are indissolubly chained together, and that one follows the other in inevitable succession equally feel that this ordination -- this chain cannot he changed at the cry of man. To suppose that it can is to place the whole harmonious system of nature at the mercy of the weak reason and the selfish wishes of humanity. If the purposes of God were not wise, they would not be formed: if wise, they cannot be changed, for then they would become unwise. To suppose that an all-wise Being would alter his designs and modes of proceeding at the entreaty of an unknowing creature, is to believe that compassion would change his wisdom into foolishness ... If the universe is governed by fixed laws, or (which is the same proposition in different language), if all events are pre-ordained by the foreseeing wisdom of an infinite God, then the prayers of thousands of years and generations of martyrs and saints cannot change or modify one iota of our destiny. The proposition is unassailable by the subtlest logic. The weak, fond affections of humanity struggle in vain against the unwelcome conclusion."

"All the events said to have been witnessed by John alone are omitted by John alone. This fact seems fatal either to the reality of the events in question or to the genuineness of the Fourth Gospel."