The sign of trouble is not just the change itself, with all it says about the decline in advertising revenue and sales. Obviously this is serious, and has all stakeholders - managers, journalists, freelancers, printers, readers - worried.

But the comments make it clear that there are other failures at work. When readers vow to cancel their subscription because Fairfax will be publishing in a compact size, they are not simply expressing a trivial preference. They are demonstrating a very weak grasp of facts and reason.

It is ignorant, because many fine newspapers are now in tabloid format: The Independent, for example, is a smaller sized publication, and maintains a very high editorial and journalistic standard. It seems sadly provincial to see tabloid format as nothing but gutter journalism or a paparazzi glossy.

This is also irrational because it fails to grasp basic logic. Some salacious and superficial newspapers are tabloid, but not all tabloids are salacious and superficial.

This failure of evidence and reason suggests a more profound problem for newspapers in Australia, and perhaps internationally. Some of their most committed readers - or at least those who comment regularly - cannot think properly. This does not mean they cannot do their jobs, raise families, pay off mortgages. It means that the higher-order abstract thinking required to make sense of modern ethical and political debates is seemingly beyond them. They cannot dissociate a newspaper's format from its content. How on earth can they expect to assess foreign policy or welfare reform?

And if long-term newspaper readers cannot demonstrate the basics of logical thought and fact-checking, what exactly have newspapers been doing these past decades? Clearly not helping some ordinary citizens to inform and orient themselves.

The commenters having their say on the decline of newspapers are living proof that this demise pre-dated financial failure.

The point is not that newspapers ought to single-handedly replace educational institutions - though clearly schools and universities are failing in their pedagogical role.

The point is that newspapers, by introducing readers to important facts and arguments, have many opportunities to raise the overall standard of debate. And, for a vocal group of readers, they have failed.

How might they do better? One remedy is these very opinion pages. First, they require what's often called ''balance''.

Balance is about including a diversity of opposing positions, all of equal authority. This authority can be because of evidence, logic, expertise and status.

The point is that newspapers ought to ensure that, on any given issue, there are a good variety of clear, well-argued and well-evidenced positions. This does not mean giving cranks equal footing with experts, or a handful of dissenters with a global peer-reviewed consensus.

But it does mean making sure that the newspaper does not become a narrow mouthpiece for any one interest group.

This balance, in turn, requires sustained argument from both sides, of the sort rarely seen in contemporary Australian newspapers.

In short, whatever physical form newspapers take, one vital commitment is to robust debate, which gives readers the opportunity to refine their arguments and clarify their evidence.

Dr Young is a philosopher and writer, and the author of Distraction. His next book, Philosophy in the Garden (MUP) will be out in November.