Buildings are about belief. These buildings in particular, marking the transition from penal colony to global city, evince a faith that this motley crew could make it. Quarrying, carving, corbelling and arcading the very stone of the place into richly hand-decorated halls and stairs and streets, they landmark not just our city but our narrative, implying a confidence in our fledgling public institutions that contemporary buildings cannot begin to match. Bridge Street may not be the Rue de Rivoli, but these buildings can never be repeated or, once sold, reacquired. Truly, they are our icons. I know. We don't use the word heritage any more. Like feminism, like environmentalism, like refugee compassion, heritage hasn't just fallen off the agenda. It has been kicked, whimpering, under the table and out into the gutter. Perhaps it is Gough's death that throws all this into such sharp relief. Perhaps it's inevitable pendulum stuff. But, whispers Cassandra, it is dangerous. The hard-won achievements of 50 years are drowning under what Thomas Merton called "the murderous din of our materialism." Civilisation is the collective recognition that there are things as important, or more important, than material profit. Buildings that enrich and delight us beyond the merely necessary reify this belief. But it's not just buildings, and it's not just Sydney. Whenever some outspoken female is anonymously blagged on Twitter as a "dried up menopausal feminist" or some activist as a "rabid greenie" I am reminded how easily civilisation vanishes, like some western mining town that wipes itself from the planet every few years in order to expand the pit.

"Civilisation's veneer be cobweb thin, my dear, and as easily vanquished" muttered Cassandra the other day, when Melbourne's treasured Palace Theatre was part-demolished without authorisation. Again, when Premier Mike Baird insisted this week that nothing – not corruption, not enquiries, not public fury – will "derail" the truncation of Newcastle's rail line, Cassandra muttered dark truths. Of course, civilisation has always been fragile. Relax your guard, nod off at your post, and whammo! There's another gaping gash in the fabric. But sometimes the forces of darkness seem especially aligned at every level and shine blackly through. The sandstone precinct of Bridge and Macquarie Streets is the built equivalent of the ABC, proof of a young country's will to rise transcend its cowboy past by the simple, defiant act of creating a dignified public realm. The government's determination to flog them betrays a deep disregard for the public spirit that built this state and this country. True, sale is not demolition. London's Harrods was sold and survived. But that was different. It wasn't a public building. A grand building among thousands it was loved but not symbolic. Plus it was hugely protected by law. The Bridge Street sandstones are ours. They are beautiful, rare, redolent with public symbolism and almost entirely unguarded by heritage law that can only be described as pathetic.

The two buildings for sale are James Barnet's Department of Lands building (1880-93), on Bridge between Gresham and Loftus Streets and George McCrae's Department of Education Building (1915), between Loftus and Young. Together with Barnet's Chief Secretary's Building (1881-1910), corner Bridge and Macquarie, they comprise the flavor and grace of Bridge Street sandstone. It's not as if we have no appropriate public uses. The "Bridge Street High" idea floated recently by a group of distinguished architects including Richard Leplastrier, Peter Myers, Philip Thalis and Beverley Garlick, is brilliant. Sydney is desperately short of inner-city high schools and Myer has drawn a scheme for a 500-person auditorium within the courtyard of the Education building, the rest of which could easily adapt to high-school uses with a garden roof. The same architects propose the Lands Department, with its six-metre ceilings, glorious domes and massive sixty-metre gallery spaces, as a downtown extension of the Art Gallery. While the Chief Sec's building is proposed as a natural home for the ICAC, now so crucially engaged in cauterising our diseased body politic yet stuffed into that ghastliest of office buildings, Stockland House. Can the government not see its way to invest in Sydney's public life? But the other compelling argument against the sale of these buildings is the sad, sad state of our regulatory framework. The Commonwealth heritage law is worse than pathetic. All real power sits in the NSW Heritage Act, fought for and won in 1977. Even this was always more "if you please" than "thou shalt" but it was better than nothing until Gabriel Kibble half-devolved control to local government and Ministers Knowles and Sartor, with their relentless bombardment of amendments and exceptions, turned the act into a colander.

Now a building can be listed from streetscape to door-handles and still fall without a squeak. The National Trust is too busy having high tea with John Howard to say anything useful and the Historic Houses Trust, however it rebadges, has disappeared up its own in-fighting. New is great, but vital futures grow from revered pasts. Our buildings are our story and our self-belief. We've kept Bridge Street this far. I'm hoping, unlike Troy, we see the enemy within before it's too late. Beware visitors bearing gifts. Twitter: @emfarrelly