When I read Meredith Burgmann’s new book Dirty Secrets - Our ASIO Files, I felt a range of emotions.

At times, the stories of 26 Australian political activists who were granted access to their secret ASIO files made me angry. After all, here was a secret government agency literally spying on people who were simply exercising their right to participate in our democracy. But the biggest take-out for me is hope.

I should explain. During the second half of the 20th century ASIO reasoned that the activities of these 26 people, including well-known Australians like former high court judge Michael Kirby, journalist Phillip Adams and horticulturalist Peter Cundall were potentially dangerous people worthy of expensive and time-consuming surveillance.

But when we consider the issues that were the focus of their activism – opposition to the Vietnam war and apartheid and support for Indigenous land rights, women's liberation, gay rights and trade unions – things look a little different. History shows us that the causes for which these activists fought have largely been realised, and views once seen as extreme are now considered mainstream.

Facebook Twitter Pinterest A women's liberation demonstration. Photograph: John Olson/Time & Life/Getty

Last year the funeral of Nelson Mandela saw him recognised as one of, if not the most, inspirational figure of the 20th Century. There is a broad acknowledgment that the Vietnam War was a mistake. A woman's right to choose is a given for most Australians and we have had a female prime minister, governor general and female leaders of every state and territory government, except for South Australia.

So the battles of the last century that were considered subversive at the time, have largely been won. That’s why this book inspires hope. It is an affirmation that, in spite of the best efforts of those who seek to hold back progress, history moves forward. It is also a reminder to the progressive left side of politics that a just cause will win in the end, whatever people say at the beginning. If the objects of the progressive left last century are now considered mainstream, issues that should inspire today’s activists will also find acceptance in the future.

So while we have a prime minister who believes that the science behind climate change is, in his words, absolute crap, a day will come when that comment will be seen as absurd. Abbott is on the wrong side of history, his place defined not by leadership, but by resistance to change.

I know some of the 26 Australians who feature in this book personally, so I know their activism came from the best of motives. Those that I know were not planning to overthrow the state in violent revolution or to diminish the rights or quality of life of any individual or group.

While reading their stories invigorates my reformist spirit, it also reminds me that one of the problems with the progressive left is that we consistently fail to celebrate our many victories. Often that is because, having won one battle, we hasten to the next challenge. The work of reformers is never complete.

Conservatives don’t have that problem. By definition, they fear change. True conservatives fear anything that is at odds with the status quo, even to the extent of being unable to recognise when the status quo represents injustice. And reactionary conservatives actually want to tear down the gains of the past.

This brings me back to 2014 and Tony Abbott. His recent budget is not a plan for the future, but an attack on the gains of the past, like universal health care and equality of access to education. His position on climate change is an affront to anyone who is prepared to give the planet the benefit of the doubt. Abbott has defined himself by what he is opposed to, not what he supports.

However, as this book shows, the good news is that history is frequently kinder to progressives that conservatives. While progressives are often vilified at the time of their advocacy, they are the creators of the positive narrative of human advancement.

The apology to the Stolen Generation went from being a radical concept to one of national celebration when Kevin Rudd lifted our hearts with the sincerity of his words. A year earlier, the conservatives were still arguing that this would be divisive rather than a positive step on our national journey.

In the same way, people will one day look back at Abbott’s views on climate change and say: “really?”