It has taken me a long time to see this, and you can laugh at me if you like. But here goes.

Photography is the serious art of our time. It also happens to be the most accessible and democratic way of making art that has ever been invented. But first, let's define photography.

A photograph is an image captured on film, paper or – most commonly now – in digital memory. Photography also includes moving images captured on film or video. Moving or still, we all know a photograph is not a pure record of the visual world: it can be edited and transformed in infinite ways.

Moving or still, and however it is taken, whether by pinhole camera or phone, the photographic image is the successor to the great art of the past. It is in pictures by Don McCullin or films by Martin Scorsese that we see the real old master art of our time. Why? Because photography relishes human life. The greatness of art lies in human insight. What matters most is not the oil paints Rembrandt used, but his compassion. Photography is the quickest, most exact tool ever invented to record our lives and deaths – 17th-century painters would have loved it.

An Indian ragpicker in a market in New Delhi. Photograph: Kevin Frayer/AP

Or if David Hockney is right, they did love it. Vermeer almost certainly used a camera obscura to compose his scenes. Hockney believes that Caravaggio and many more artists used a "secret knowledge" of early cameras to perfect their almost hallucinatory understanding of the visual world.

However they did it, they painted the flux and drama of real life. From birth to death, great art is a sequence of moving pictures of the human condition.

Today, photography is the only art that seriously maintains this attention to the stuff that matters. Just look (as the world is looking) at this week's incredible photographs of a family surviving a wild fire in Tasmania. Here is the human creature, vulnerable and heroic.

A doll in the mud after torrential rain in Israel. Photograph: Ariel Schalit/AP

Little of that raw human stuff makes it into the over-refined world of contemporary art, and when it does, it is often because photographic images have been accepted as art. 2012 Turner prize winner Elizabeth Price harrowed London's Tate Britain with images of horror and fear in a work that epitomised the power of photographic art.

But the photography that meets the critieria of the art world is just a tiny sliver of the camera's artistic riches. From news images to the Hubble telescope, Photography is the art of real life – however manipulated. And real life creates true art.