This 1999 essay by Roger Bradbury is an intriguing answer to the question posed by its title.
Unfortunately, I have been unable to find a particularly clean version of the essay on the ‘net. What is available (as of 2019-05-21) is a readable if somewhat grainy PDF of the essay which can be found by Googling for
"just what is science anyway" "Bradbury"
If you get the same results that I got, the second hit will be a link to the PDF file for Roger’s essay.
Regardless of whether or not the above search works, Roger expanded on his answer in what became chapter 2 of the 2006 book Complex Science for a Complex World published by the Australian National University (ISBN 1 920942 38 6). That book is online at the URL below. While the entire book is likely to be an interesting read, Roger’s contribution is chapter two which is titled “Towards a New Ontology of Complexity Science”.