Today will see the first national teachers’ strike for 21 years. Around 8000 schools will be disrupted, either partially or fully closed.

Teachers are skilled professionals. They do a tough job, working long hours and often enduring difficult working conditions. They also play a key role in society, so it’s important to attract good staff to the profession.

On the other hand, teachers are already well paid. According to Jim Knight, the Schools Minister (admittedly not a neutral source), the average salary for a teacher is £34000.

So there’s an interesting argument to be had about teachers’ pay.

However, for the most part that isn’t the argument that’s being had. Instead, the argument from the NUT (the teachers’ union that’s called the strike) that we’re hearing most is all about past levels of pay. Christine Blower, the NUT’s acting head, put it like this:

What we’re saying to the government is, if you really do value teachers, then make sure that they’re paid at least at the level of inflation - which we take to be the RPI [Retail Price Index], which is 4.1%.

The NUT’s argument is that the 2.45% pay rise that teachers have been offered is below the rate of inflation. If teachers’ pay rises more slowly than the rate of inflation, then their salaries will buy less than they used to; in real terms, teachers will have had a pay cut. And the NUT won’t stand for a pay cut.

There’s nothing in that argument about why a pay cut for teachers would be such a terrible thing, though. It doesn’t argue that teachers deserve more than they’ve been offered, or that a fall in teachers’ pay would hit recruitment, or anything like that. Instead, it’s a straightforward appeal to history, arguing that next year’s pay should be the same (in real terms) as last year’s pay.

Appeals to history are, of course, fallacies. That things were a certain way before doesn’t prove either that it was right that they were that way or that they should continue to be that way. The NUT needs to shift their focus to a better argument.

It probably wouldn’t be a great idea to try to explain that to your teacher, though. Except, perhaps, your Critical Thinking teacher.

The Tory party today attacked Labour for what it claimed is excessive spending on public relations: over £322 million / year. This includes the wages of over 3200 press officers. Things weren’t like this under the previous government, the Conservatives have pointed out.

As it was reported in a Guardian article, the Conservatives’ complaint was supported almost entirely by a comparison of current and past figures on spending. The article repeatedly contrasted the current figures with those from nine years ago, when the Tories were last in charge.

In 1997 the cost of government PR was just a third of the current £322 million at £111 million, it points out. Back then there were just 300 press officers in Whitehall, compared to around 1800 today, it continues. Tax-payers money is being wasted, it is inferred.

Now the government spending on PR does seem over-the-top. However, simply comparing current figures with previous figures doesn’t prove that.

Things have changed since 1997; the rise in 24-hour news and the increase in demand for news that it has created, for example, means that there is greater pressure on the government to provide information to the press than there was before. Other factors may also justify a rise in spending.

Besides, for all that is said in the article it may be that the Tories were guilty of under-spending on public relations. If all we have is a comparison of two sets of figures, then how are we to decide whether current spending is too high or past spending was too low?

Simply looking at the past and assuming that things should be the same now is a logical error: the appeal to history fallacy. A little more is needed to show that Labour have been over-spending on spin.