Only Bostonians could have this particular argument about parks:  Some say they should be passive—places to stroll, admire plantings and contemplate matters metaphysical. Others say we should fill them with activities—skating, fenced-in dog runs, swimming pools, restaurants. You can see the different philosophies when you compare the Hudson River Park to the Esplanade. They were designed for different purposes.

Sometimes the different park philosophies come to a head. There were complaints from some quarters when Tom Kershaw succeeded in turning the Frog Pond in the Common into a skating rink. Objections to creeping commercialism surfaced when the non-profit Bostix wanted to build the attractive kiosk now conveniently located in Copley Square. A few grumps loudly complained about the tackiness of the holiday lights that now illuminate the Commonwealth Avenue Mall. Park advocate Henry Lee’s comment was my favorite in support of the lights. “Christmas can’t be too gaudy for me,” he said. But others’ attitudes seem to suggest that this city breeds residents who don’t like to see people enjoying themselves unless it is involves reading a book.

So maybe it’s good that the Rose Kennedy Greenway isn’t really a park. This expanded median has sidewalks lined with perennial beds, sometimes attractive, sometimes a bit sparse, and a few features the value of which are still debatable. And its caretakers stir up controversy about once a month.

But this “park” doesn’t suffer from the passive-active debate. Everyone is pretty much for activity. And a small grouping of promising installations is rising. They aren’t perfect. But they might work.

Imagine the location. Quincy Market is on the land side. Christopher Columbus Park and the Marriott are on the harbor side. Two pieces of the grouping are under construction now. One is the Harbor Islands pavilion—a bit flimsy looking, but it will provide a service. Toward the north is the controversial Armenian Heritage Park, which will be anchored by a truly unpleasant dark, bulky zig-zag sculpture, the one advantage of which is that it isn’t a sentimentalized cartoon like the Irish famine memorial in front of Borders that makes people roll their eyes. A possibly redeeming feature of the Armenian Heritage Park is that it is supposed to have a granite maze. Let’s hope for the best.

In between these two opposing forces lies a hard surface that has held a carousel for the past two summers. I’ve ridden this carousel several times with adorable children who are related to me.

An anonymous donor has now come forward to contribute up to one million dollars to install a permanent carousel. It is hoped that it will be open from April school vacation to New Year’s Day. Four classrooms of children, two of which come from downtown schools, the Eliot in the North End and Advent on Beacon Hill, have helped create ideas for the jumpers, standers and chariots—that’s what the riding sculptures are called, we learned at a recent community meeting. (My favorites were a drawing for a whale spouting real water and a scallop shell that opens and closes.)

The Greenway Conservancy is almost at the end of the carousel feasibility study, assisted by a husband-and-wife team of carousel makers from Newburyport. An occupation like that makes you realize that Massachusetts jobs aren’t only of the bio-tech variety. It looks as if this carousel will happen.

The temporary carousel has been good business. It’s cheap—$3 a ticket. It has attracted 80,000 riders this year. It has thrown off about $60,000 in profit.

I’m hoping the Conservancy ignores the fear-mongerers who predict lawsuits over injured kids if planners install a brass ring for riders to grab. After all, French children have circled for decades in the Luxembourg Garden trying to catch the ring with their wands, and they have survived. The competition set up by trying to catch the brass rings attracts older children who’ve realized that riding a carousel is a bit anticlimactic after all the anticipation.

But the main advantage the Conservancy might realize in these three very different installations in a short distance is landscaping that ties them all together, unifying disparate pieces, providing shade and benches so parents and grandparents can watch the kids and providing a reason for the landscaping to be there in the first place. Good landscaping might make the pavilion seem less wispy, the memorial less foreboding and the carousel as permanent as the one in Paris.

We’ve got a way to go in the Greenway, but things are not as bad as the complainers say, and they’re not as good as Conservancy leaders maintain. Gradually, as good ideas take hold within the Greenway and buildings along the perimeter open up to the park, its promise can be realized.

Every time I cross it, walk through it or drive along it, I’m amazed. What were those 1950s planners thinking in building such ugliness? What a blessing that the overhead roadway is gone.