It has been usual to divide Ruskin's life around the year 1859/60, when he was forty years old. Before that time he was essentially an art critic concerned with changing received attitudes to art, and after it he was a social critic obsessed with the evils of industrial society and preaching a new and radical social order. The first phase was dominated by the influence of Turner, the second by Carlyle. The division is basically sound, provided it preserves some impression of the unity of Ruskin's thought. There was, clearly, development with the unfolding of the years, and with the addition of new themes, but Ruskin's chief characteristic as a thinker was his consistency. In the later parts of his life his writing, often emerging from beneath overlapping sequences of mental instability, was increasingly filled with seemingly disjoined and sometimes even intellectually incoherent illustrations and subjects: but despite first appearances the consistency actually held; there was ‘conscious design’ beneath the ‘wide diversity of interests’. Interpreters have appreciated the astonishing penetration of Ruskin's analysis, whether of art or of society, and they have sympathized with the power and sentiment of his assault upon the social evils of his day. Despite the evident clarity of his writing, however, he actually remains difficult to categorize.

He has been known as a Christian Socialist. The title does not rest easily upon him. His Christianity was not susceptible to an institutional expression, and his understanding of religious belief underwent several changes during his life and was rarely precise.