"Anyone who believes in indefinite growth in anything physical, on a physically finite planet, is either mad - or an economist". Kenneth Boulding, JFK's environmental adviser.
Yes money can grow indefinitely, but it is not a physical thing. The amount of money that exists continues to grow, as it must because of interest, but the amount of actual useable resources does not. Therefore our priority must be to make the best - sustainable - use of them.
Don't be sidetracked by talk of deficit reduction. Reducing the deficit is only reucing the amount of money that's added to the National Debt in a year.