In her book Freethinkers, Susan Jacoby constantly highlights how often great thinkers are neglected from the American historical canon due to their criticism of religious authority or social norms. This may seem odd to anyone who knows even a little about the Founding Fathers and, for example, Abraham Lincoln – but we know of these gentlemen due to their role as presidents and founders of the very nation itself, despite their antagonism toward organised religion and its “truths”.

During the late 18th century, many thinkers – prominently those fighting for abolition and women’s equality, which were often united causes – optimistically presumed that the deliberate neglect of powerful activists would be eroded, since the values themselves would come to fruition; and, thus blooming, all would recognise those who originally distributed the seeds of such knowledge. But even today, the names William Lloyd Garrison, Lucretia Mott, and Ernestine L. Rose, are quite forgotten by those who more confidently remember other names within the era.

All were great reformers and thinkers in their own day, but I particularly have a fondness for Rose, who was active in her denunciation of all religions, and her advocacy for abolition and women’s equality. Thankfully, many of the enlightened and progressive Quaker community could withstand their religion being torn a new orifice, so were quick friends with this immigrant Jewish thinker – but most others, including newspapers and pulpit bashers, could barely stand liberal Quakerism with its educated women and liberal views on race equality. In a 1853 convention, Rose touched on an important point.

A child may be made to believe a falsehood and die in support of it, and therefore there can be no merit in a [mere] belief. We find in the various sects of Christendom, among the Jews, [etc.], in fact, throughout the entire world, that children are made to believe in the creed in which they are brought up.

This is radical enough for many people today, let alone before the publication of Origin of Species. But, as Jacoby highlights, in contrast to Rebecca Gratz, a Jewish philanthropist, Rose is largely forgotten because of her secular advocacy: “The issue is not whether Gratz or Rose is the more important historical figure but that the memory of a pious founder of charities is much more likely to be preserved than that of an atheist who challenged the norms of her own generation and subsequent ones.”

Reflecting on this later, Jacoby hits on what has been the most remarkable encapsulation of this idea I’ve encountered so far in her remarkable book. Responding to the 19th-century optimism that secularism would erode conservatism, that Enlightenment values would be cherished proudly in America in the future, Jacoby replies in a warning and observation that all secular organisations and individuals ought to heed today.

Values are handed down more easily and thoroughly by permanent institutions than by marginalized radicals who, even if they change the minds in their own generation – as the abolitionists did – are often subject to remarginalization in the next. Every brand of religion maintains and is a permanent mechanism for transmitting ideas and values – whether one regards those values as admirable or repugnant. Secularist movements with their generally loose, nonhierarchical organization, lack the power to hand down and disseminate their heritage in a systematic way.

It is because so many of us are against preaching, against dogma, against “leaders” knowing better than us through mere assertion rather than critical engagement, that we are almost by definition marginalised even when part of groups with fellow thinkers. But this warning and observation from Jacoby nicely encapsulates why the ideas require constant advocacy within the public sphere.

The ideas live and die on the lips of advocates. If we say them only to each other, they become impotent. We require these ideas to be defended, since it will be those who are for dogma, for preaching, who then assert what is good or right for the rest of us. As John Stuart Mill highlighted in 1859, individual freedom is not a position one reaches or a property acquired; it is a constant state of opposition against powerful bodies that seek to control us in myriad ways. It is through active engagement with your freedom against those who are paternalistic and bullying that you maintain your individual freedom.

No wonder then that it requires constant engagement and why those who do advocate it beautifully, as Rose did, will be forgotten since, if possible, it will be those who advocate freedom and those who challenge norms that will be either actively or subtly rubbed out of history. It is not their names that matter, but their ideas. But one way of keeping their ideas alive is to defend their reasons for defending their ideas in the first place. In order to do that, we have to know who they were. This isn’t reverence for their memory, it is the ability to engage properly with their entire body of thought.

Or as Jacoby puts it: “The most regretable consequence of the discontinuity in the record of American rationalist dissent is that its moral lessons must be relearned in every generation.”