MARY Midgley has never been a philosopher who lived in an ivory tower.

Right now, her home is a small retirement apartment in a sheltered housing complex called Pilgrim's Court in Newcastle. It is, she says, very well designed for her stage in life, with its mini-kitchen, bedroom, and small living room, which she has functioning as a perfect philosopher's office: armchair in the corner, desk with computer, a few shelves of books, and a window seat covered in sections of the Guardian and copies of periodicals such as The RSPCA and Philosophy Now.

When I arrive, the 95-year-old, who remains one of the UK's most highly regarded moral philosophers, and a voice of common sense in an often esoteric and perplexing field, is sitting in an armchair, a book, Homage To Gaia by the scientist and environmentalist James Lovelock, at her side. She doesn't rise, since currently she is only really moving around with the help of a mobility aid.

She is, she says, still writing: currently working on an afterword for a book about her philosophy and also on a talk she will give next month at the Edinburgh International Science Festival, when she is awarded The Edinburgh Medal for her contributions to the "wellbeing of humanity".

"There's nothing wrong in here," she says, pointing to her forehead. "It's just my legs. I'm terribly lame." The problem, she explains, was worsened by the fact that she couldn't manage the stair in her old house, not far away in Jesmond, so didn't manage to get enough exercise. "If I'd died as my parents did in my 80s," she says, "it would have saved a lot of bother because I wouldn't have become lame."

But nor would her two most recent books have been written. Her 2010 book, The Solitary Self: Darwin And The Selfish Gene, attacks the idea that individualism is written into who we are by our genetic make-up - and continues the long-running row between Midgley and the evolutionary biologist Richard Dawkins. Last year, she published Are You An Illusion?, which countered the notion that there is no self, only chemicals and neurons. The book was triggered by a quote by Francis Crick, the discoverer of DNA, who wrote: "You, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behaviour of a vast assembly of nerve cells and their attendant molecules."

Midgley was "shocked and bloody horrified" when she read this. She thought then: "I shouldn't have to do this, because this notion about being an illusion is perfectly silly, but it seems I do."

One gets the impression that Midgley doesn't keep on writing just because she enjoys it, but because she thinks the world needs her to counter prevalent ideas she considers "silly" or "ridiculous", and bring us all back to "talking sense" - and because she believes such questions should not be purely left to scientists. As the philosopher Roger Scruton has put it: "Midgley's view is that philosophy, in leaving the question of human nature to the biologists, has betrayed its mission."

Midgley was in some ways a late starter - she published her first book, Beast And Man, aged 59 - so perhaps it seems also right that she is a late-finisher, reluctant to quit interjecting whenever she sees some new "silliness".

Much of her career-long philosophical battle has been against what she describes as scientism (the belief that empirical science is the most authoritative world-view or most valuable part of human learning). It's a subject she will be discussing when she comes to Edinburgh, where she will, she says, talk about how "the sort of reverence for science is quite detached from anything that's achieved by actually doing science".

Richard Dawkins has long been one of her prime targets. It's as if she feels his "selfish gene" concept is a tiresome gnat that she has to keep swatting away. "I didn't read TheSelfish Gene [published in 1976] till a long time after it came out," she recalls, "But when I did, I was horrified. Personally I thought it was a disaster." She then went on, in 1979, to write a controversial article. "There were two things that I was objecting to," she recalls, "one was that selfish point of view, the other the identifying of the gene as being the person, the agent that's in charge. It's the only time I've written in a really bad temper."

At the time, Dawkins wrote that he was "taken aback by the inexplicable hostility of Mary Midgley's assault". He pointed out that he "was not really writing about man but about the evolution of life". He was particularly upset by one remark, in which Midgley revealed: "Up till now, I have not attended to Dawkins, thinking it unnecessary to break a butterfly upon a wheel."

"The real joke," Midgley says now, "is that Dawkins picked up the mistaken idea that I had said that I hadn't read the Selfish Gene." This turns out not to have been true, though she notes, "he's been put right about this by a number of people. A number of people have said this isn't true. But he still goes on saying it."

Midgley was born Mary Scrutton, 10 months after the start of the First World War. Her mother, a Scot, came from the Borders, and she recalls being brought up in a "very intelligent Anglican household" in the south of England. Her father was a parson who had been brought up without religion as a child but "somehow got it in his teens" following a conversion experience. As a young man he went as a chaplain with the forces in 1915, and found himself at the Front having to explain to them why they were dying. This, says Midgley, was "the experience of his life" - and from then on he became a campaigning pacifist, determined to oppose war in every way possible.

Midgley studied classics at Oxford, where her contemporaries included Iris Murdoch (who became a close friend and bridesmaid at her wedding), Mary Warnock, Elizabeth Anscombe and Philippa Foot. She met her late husband Geoffrey Midgley, also a philosopher, there. He later took up a post at Newcastle University, where they would remain, and where she would leave off pursuing her career for many years while she raised three children. She and her husband believed that philosophy was to be found in chats in the common room and real life moral issues, rather than some of the more recondite territories other contemporaries were exploring. "We were sick of a lot of what was going on in Oxford - we thought most of them were wasting their time. So without setting it up as a policy, we got terribly interested in what was going on locally."

For all Midgley doesn't shirk at attacking other academics for their silliness, she's also not short of praise for those whose ideas she believes in. James Lovelock, she considers the "next big thing after Darwin". Currently she is "rereading" Lovelock's memoir. "He's brilliant isn't he?" she says. "He looks at things on another scale. The importance of him still isn't really recognised. I was just reading how when he was young he quickly showed that there couldn't be life on Mars because of the atmosphere. But people are still after it - they still want there to be life there."

He is, Midgley says, a friend - and they are doing a "conversation" event together at the Edinburgh Science Festival. Both were born in the same year, and remain intellectually sharp and influential, even in their mid-90s. "I read his first book and at some point we got together and we have done so repeatedly. It's not easy to see each other because here am I in the north-east of England and he's in Dorset."

Midgley shares Lovelock's fears over climate change. "The trouble with taking climate change seriously," she says, " is that it means you have to do a lot things you don't want to do. This is going to affect our lives. The only parallel I can think when people have done that is the beginning of the Second World War. People at once were willing to change their minds and sacrifice this and that."

Midgley lived through, and witnessed, that societal change. Though she herself was well aware of the threat of Nazism, having read about it in the New Statesman and even witnessed it first-hand on a trip to Vienna in 1937, many in the run up to the war had not been worried. "The climate of the country was pretty conservative," she recalls

She was, however, impressed at the way "everybody, the general public, seemed to get it right away - and there was a great shift from general selfishness to being pretty self-sacrificing in a lot of ways." That's the kind of thing, she says, that needs to happen now. "It hasn't happened and I can't make out whether it may do."

She always describes herself as not religious. Is she agnostic? "If I'm asked, 'Is there a god?' I don't quite know what that is," she says. She does, however, talk about something she calls a "life force", and adds: "I'm convinced that the whole of creation is doing something."

Now in her 10th decade, Midgley - who lost her husband in 1997 - is not preoccupied with death. "I never did think much about it," she says. "There are some people who are always frightened of death. I haven't been. I just sort of think - wait till it comes, so to speak."

What's striking is that, even though Midgley only moved in here three weeks ago, there's nothing very sentimental in the way she talks about this new home, or her leaving of her previous house. While other residents, she says, have photographs of their old home decorating their walls, she has chosen paintings. She appears to be enjoying the space. Friends call, she talks to people on the phone; she has been going to the coffee mornings that are held for residents. Among the most difficult issues, she says, was deciding which books to bring. "But I don't seem to read so much in a day as I used to," she says. "I do it more slowly."

It seems a busy existence. At the end of our interview, I ask if she might want a rest. But Midgley has something else planned. She will go out for a walk. She needs her exercise. She plans to be getting about soon without the mobility walker again and is training her way up to it.

Mary Midgley will appear in three events on April 7 and 8 at this year's Edinburgh International Science Festival, including a special in-conversation event with James Lovelock at The Queen's Hall