'There is such a thing as toffee, its just not the same as mackerel"

The great debate will make it a night for watching political language, though close campaign watchers may find the leaders offer tried and tested lines to the large national audience rather than adding anything new to the political lexicon.

There were some interesting responses this week to Next Left's observation that the original author of David Cameron's defining political argument - "there is such a thing as society; its just not the same as the state" - is in fact Margaret Thatcher, not Samantha Cameron.

A number of people pointed out that this is simply a truism. I am grateful to Christopher Cook, a Financial Times leader writer who formerly worked for David Willetts in the cause of civic conservatism, for surely clinching the point in a twittered observation:

@nextleft It is, indeed, a truism. Replace the nouns with any two others and it still makes sense

"There is such a thing as toffee, it's just not the same as mackerel."

Try it yourself. "There is such a thing as Easter, its just not the same as Christmas", as the Archbishop of Canterbury may wish to muse wisely as part of his next sally against excesssive secularisation, and so forth.

The shared foundations of Cameronism and Thatcherism become less remarkable given that everybody can agree that 'different things are not the same'. (This may have been one of the first things David Cameron learnt in studying formal logic as part of his Oxford PPE degree, so his tutors may be impressed that he has derived a new political philosophy from it).

Yet, by the same token, Cameron's defining argument can no longer in itself provide proof that the party has changed.

If there is such a thing as Cameronism, just how it is not the same as Thatcherism?

That remains a question the leader has refused to answer in any substantive way. But an answer surely remains essential for David Cameron to identify what he will do differently so that similar sounding arguments for more society and less state do indeed deliver, as he desires, the opposite results: less, rather than more, inequality this time around.

Nor does the claim that his political opponents can not tell society and state apart make much sense. After all, Cameron can not think that a strong society can never choose to act collectively through the state - or it would be quite impossible for him to embrace and celebrate the Fabian, collectivist NHS as enshrining our social commitment to each other, or to commit to increasing Britain's overseas aid budget to 0.7% of GDP.

Ironically, too simplistic an advocacy of "do it yourself" government could mean that is Cameron, rather than his political opponents, who risks conflating government and society.

The antidote might be found in musing on another, as yet voiced, insight of Cameronism:

"There is such a thing as the state - and that not always the same as society".