Charles Watts, who founded the Literary Guide in 1885, had everything one could wish for in an editor and publisher. He was patient but punctilious, tolerant but firm, and decisive but self-effacing. He encouraged controversy in his pages, though he shrank from it himself. He took no payment for his editorial services (he regarded himself as a humble printer by trade), but he was conscientious about paying his contributors promptly at the full commercial rate. From an early age he had spent most of his waking hours in his offices and printshops in Johnson's Court, on the North Side of London's Fleet Street, and he continued to shape the monthly Guide until his death in 1946, without skipping a single issue in more than 60 years.

But he was averse to the limelight, and never willingly put his opinions or even his name before the public. His name was however a source of confusion. The founder of the Literary Guide was a master of self-effacement, but he was understandably proud of his father, who was one of the stars of the freethought movement in Victorian Britain – a popular lecturer and pamphleteer and founding secretary of the National Secular Society – and who, unfortunately, was also called Charles Watts. In 1874, Charles Watts senior had taken charge of a well-established secularist printing and publishing business in Johnson's Court to create the firm of Charles Watts, but a few years later, when he started spending much of his time in the United States and Canada, he decided entrust it to his son and namesake, who was then in his early 20s. When Charles Watts junior spread his wings and started his own periodical, a casual punter might have taken him for an egomaniacal show-off, since its full title was Watts's Literary Guide, it was published by a firm called Watts & Co., and it brimmed with information about the activities of Charles Watts on both sides of the Atlantic. Only an initiate would have known that the Charles Watts who strode through the pages of the Literary Guide was a different person from the Charles Watts who sat quietly in the editorial chair.

In the first issue, which sold for a penny and comprised 8 modest pages, Charles Watts junior set out his ambition of filling the Guide with all the 'literary gossip' that might be of interest to freethinkers, together with 'a complete record of the best liberal publications in this country'. Before long it settled into the pattern it would follow for six decades: several brief signed articles in which the Christian establishment was criticised on every imaginable front, from science and metaphysics to history and poetry, interspersed with anonymous paragraphs (mostly written by Watts) retailing miscellaneous facts about worthy progressives from Leslie Stephen to Annie Besant, or Walt Whitman to HG Wells, not to mention the homonymous Charles Watts.

Soon afterwards, Watts organized a support organization called the Propagandist Press Committee (later incorporated as the Rationalist Press Association), which provided him with a large group of subscribers, and enabled him to expand the Guide till it averaged 20 large pages an issue, with thousands of grateful readers not only in Britain but all around the world.

Thirty years later, during the Great War, the editorial effort began to wear Watts down. He was exasperated by British correspondents urging him to denounce the war on rationalist grounds, and appalled by German secularists who were looking forward, in a spirit of scientific reason, to the military humiliation of Great Britain. In April 1918, he stepped out of the editorial shadows for the first time in his life and inserted a very small announcement stating that 'the editor of the Literary Guide… is suffering from a slight nervous breakdown,' and asking for a kindly rationalist to offer him and his family a temporary home at a safe distance from 'air-raid visitations', but not too far from his headquarters in Johnson's Court.

Watts seems to have recovered quite quickly, and in June, shortly after his 60th birthday, he wrote his first signed contribution to the Guide, under the heading 'About personal matters'. He began by noting that "few readers of the Literary Guide… know (or care) who the editor is, and still fewer… who is the managing director of the Rationalist Press Association", before admitting that he had the honour to be both. He then gave the briefest possible account of his own life, recalling that he had begun working in the dilapidated old building in Johnson's Court as a 12 year-old apprentice printer in 1870, well before his father took charge of operations there. Since then, as far as he was concerned, nothing had really changed: he had devoted himself, with hardly a day's holiday, to promoting 'heterodox literature' and 'freethought propaganda', and he had had the satisfaction of seeing the Rationalist movement prosper, in step with the fortunes of his thriving family firm.

Towards the end of the 19th century, Watts & Co started to expand from producing the Guide and a range of propagandistic pamphlets, to publishing books, including a celebrated series of Cheap Reprints which made the works of sceptical Victorians like Darwin, Huxley, Arnold and Mill available to working people at only sixpence a volume. Watts slowly realized that his operations could no longer be accommodated in the old premises at 17 Johnson's Court, and in 1924 he moved them into more modern and extensive buildings next door. (The new premises, at 2-4 Johnson's Court, would be retained until financial necessity forced their sale in 1954.)

The move prompted Watts to offer his readers a second exercise in modest reminiscence, under the title 'Twilight Thoughts'. He began by recalling that 17 Johnson's Court had been the home of the Guide and the Rationalist Press Association for nearly four decades, and he acknowledged some of the eminent supporters who had associated themselves with the place – the philosopher Herbert Spencer for example, Labour politicians like Keir Hardie (who called it 'the Blasphemy Depot') and Ramsay Macdonald, and the bombastically freethinking Marquis of Queensberry (better known now as the regulator of boxing and persecutor of Oscar Wilde).

As far as his own case was concerned, Watts admitted that his literary output amounted to 'practically nil'. On the other hand he had been able to offer a rather more personal service to certain readers of the Guide. 'Dozens of clergymen', he recalled, 'have gravitated to Johnson's Court for advice and assistance'; and he had always been happy to help them out. He would encourage them to read widely in the liberal, freethinking press, but he always treated their faith with as much respect as their doubt, and suggested that they should not be in any hurry to leave the Church. His 'heterodox clergymen', as he called them, could perform a great service by projecting progressive notions from their pulpits, and anyway they should not lightly give up comfortable livings unless they could be sure of earning a decent salary outside.

It will be clear that Watts was far from being an incendiary ideologue, or indeed a visionary of any kind. But in 1924 he commissioned his friend FJ Gould to write an article on 'Rationalism in 1950', which was in effect a Wattsian manifesto, re-affirming the rationalist belief in the historical tendency for religious belief to decline, but in a spirit of humility and without a trace of triumphalism or recrimination. Looking forward a quarter of a century, Gould prophesied that radio and cinema would come to the aid of the printed word so as to accomplish the 'final deposition of the Gods'. The new techniques of communication would prevail not only in the west but throughout the rest of the world: "Do you think they will fail to carry a message, more penetrating than the call from the minaret, to the Islamic millions?" Gould asked. "Do you think they will fear to set foot within the golden gates of Hinduism, or hesitate to persuade Benares?"

Within 25 years, the credibility of theology would have declined to the point where "the nobler elements in the old Churches will cheerfully form a coalition with science and a Rationalist social polity", and if the old religious institutions still existed it would be from ancient inertia rather than fresh conviction. Meanwhile the passions of national allegiance would have been set aside, and young people of all nations would be studying an international curriculum covering the 'history of humanity' as a whole, and circling the globe to highlight the "best contributions made to the service of the human commonwealth". Of course the speed of progress could not be predicted precisely, but there was no room for doubt about its direction: rationalists should not be surprised by occasional obstacles on the path to humanistic internationalism, and they should not despair if "parts of the programme have to be postponed to the kind consideration of 1975, or even of 2000."

Gould's deadlines for humanist progress have of course slipped by unnoticed, and the conciliatory optimism which Watts brought to the Literary Review has begun to look quaint and idiosyncratic. At the beginning of the 21st century, the vision of a future happily purged of religion and unreason is certainly not as compelling as it used to be. But Watts's quiet confidence was not an eccentric folly: it was part of a broad and powerful tradition in British cultural life, which may well have some life in it still. And in Watts's case, it was a family tradition too.

Back in the 1870s, Charles Watts senior had been swept up in a dispute that threatened to tear the secularist movement apart. The trouble was started by Charles Bradlaugh, the most famous and flamboyant of Victorian freethinkers, and proprietor of the weekly National Reformer. Bradlaugh made a practice of linking the cause of secularism to every known variety of political radicalism, and in 1877, together with his colleague Annie Besant, he decided to republish a notorious old piece of materialist propaganda, called The Fruits of Philosophy. The author, an American doctor called Charles Knowlton, started out from familiar materialist premises, stipulating that "consciousness is … a peculiar action of the nervous system", and that 'good' is simply a word we apply to anything that "gives rise to agreeable consciousness." But then he made a notorious leap to various topics that lay beyond the bounds of conventional philosophical ontology, namely various methods of contraception, and the physiology of female sexual pleasure.

Bradlaugh and Besant had always known that their edition of The Fruits of Philosophy was likely to bring them into conflict with the Obscene Publications Act of 1857, and when proceedings against them were opened they relished the prospect of further free publicity. Unluckily they had not taken Charles Watts senior into their confidence, and since the book was issued under the imprint of his firm at 17 Johnson's Court, he found himself arraigned in the dock alongside them. He naturally felt exploited and betrayed, but it was only when passages from the pamphlet were read out in court that he realized what Bradlaugh and Besant had got him into. "The Population Question is most unfairly dealt with in the said pamphlet," he wrote, "and the indecent style of its writing is calculated to degrade and bring discredit on the great principle advocated so purely by the late John Stuart Mill and others."

A group of supporters now rallied together to form a 'Charles Watts Defence Committee'. They denounced the despotic and counter-productive extremism of Bradlaugh and Besant, describing it as 'a sad chapter in the struggles for personal freedom and the exercise of freethought'. They also upbraided Bradlaugh for sacking Charles Watts from a post on the National Reformer, pointing out for extra effect that Watts had been given his appointment back in 1866 'at the dying request of his brother John.'

John Watts was the elder brother of Charles Watts senior, and he would surely have achieved celebrity in the world of radical freethought if he had not died in his early 30s. In the 1850s, having completed his apprenticeship as a printer, he set up his own publishing business, specialising in polemics against the noisier Christians of his time, notably the bearish and ebullient Rev Brewin Grant. He also published one of the great forgotten documents of Victorian secularism – a brief anonymous autobiography called Theological Experience: a journey from Christianity to Freethought.

The author of Theological Experience (who has never as far as I know been identified) tells us he was born in 1824, and brought up as a strict Scottish Presbyterian. When he was 11 he encountered a group of Christian Chartists, his theology 'crumbled away', and he began to call himself a Socialist, an Owenite, and an Infidel. Over the following 20 years his commitment to freethought deepened, but his hostility to religion softened too and he now found that he was "much less annoyed by theological zeal, than by freethinking indifference." Modern freethinkers, he said, should remember that the abandonment of religious belief need not entail discarding all forms of ritual and indeed reverence, and they ought to consider organising secular ceremonies of their own – regular weekly meetings where communities could congregate to celebrate their births, comings of age, marriages and deaths, in the name not of God and faith but of truth and humanity.

If freethinking persisted on its present trajectory, it was in danger of becoming the preserve of ignorant, complacent, insincere and shallow men – the sort, as he put it, who would be happy if their wives took their children to church though they would reserve the right to despise them for doing so. Freethinkers, according to the anonymous author, were better at uprooting the past than at sowing for the future. They had no idea of the historic struggles that had made their freedom possible; and "now that they have liberty to speak, they have nothing to say."

John Watts's author may have gone a bit far when he suggested that conscientious atheists would do well to describe themselves as secular Christians, and Charles Watts senior certainly refused to go along with the idea. As far as he was concerned, all forms of 'supernaturalism' were equally unacceptable: "Christianity appears to me objectionable", he wrote, "under whatever name it is presented." But he was equally unwilling to follow Bradlaugh and Besant into a radical ghetto where self-criticism would be avoided and no one was capable of imagining any point of view other than their own. That was the lesson that Charles Watts junior imbibed from this father and his uncle, and the lesson he sought to pass on to the readers and supporters of the Literary Guide when he founded it 120 years ago.

In due course the Guide would become The Humanist and eventually New Humanist, and when I survey the sagging shelves of backnumbers I am not sure how well the first editor's lesson has been heeded. On the whole, we unbelievers have become more and more confident in our unbelief, even strident about, just as we have grown less and less intelligent about the things we do not believe in. Instead of studying religious phenomena, untangling their different strands and trying to work out what people see in them, we now bundle them all together as so much ignorant superstition and congratulate ourselves on not seeing any point in them. Instead of engaging in tolerant conversations with actual believers, or reaching out to the modern equivalents of Watts's 'heterodox clergymen', and even imagining that they might have something to teach us, we prefer to disport ourselves with imaginary foes like 'irrationalism' and the closely related bogey of 'fashionable continental thought', which provide easy targets because no one, however passionate about theology, would ever sign up to defend them.

And instead of attending to the problems that people are really worrying about when they think about religion, we have toyed around with exaggerated abstractions like 'relativism', 'pluralism' and 'postmodernism', defining them all in such ludicrous terms that we have no more difficulty subduing them than a cat has in defeating a ball of wool. 'We are all humanists now', according to an announcement in the Guide in 1917, and the sentiment was as obscurely self-indulgent then as it would be now. Unbelief is a struggle or it is nothing. If we really want to be humanists in the good old tradition of Johnson's Court we need to engage with some actual opponents and get ourselves a life.

Jonathan Rée is a freelance philosopher and historian