Although politicians pride themselves upon their logical, persuasive arguments, much political discourse is a logic free zone. Prime Minister’s Questions tends to be a weekly exercise in the ad hominem (“He was the future once!”), tu quoque (“Labour did the same thing in government”), anecdotal fallacy (“One of my constituents waited a year for a hip replacement”), and many more. It is sloppy logic that prevents us having a proper debate about, for example, immigration, because we hide particular examples of immigration (the Indian doctor, the Polish plumber, the suicide bomber and the foreign rapist) under the general and vague term “immigrant”, leading to a stalemate. Indeed it is vagueness and equivocal language that feature most often in poor reasoning.

Equivocal language is what makes many jokes possible (a door is not a door when it’s ajar/a jar), but it is the enemy of clear thinking and therefore of political rhetoric. And how sad it is that ‘rhetoric’ — one of the three original pillars of a liberal education — has nowadays become a term of abuse.

It’s hard to know where to begin with this piece in The Times by the Remain-supporting Matthew Parris.  He begins with the observation that:

Logic will out — yes, even in politics, in the end. So if you’re struggling with the logic of your own argument you’re in trouble.

Well, by his own definition, Parris is in trouble, and he admits as much quite explicitly.

Let me see if I can help him.

I was a Remainer. Many of us now tend to start from two premises, spoken or otherwise. I shall call them Premise A and Premise B.

First, Parris seems to be admitting here that he is no longer a ‘Remainer’. After the referendum result every UK citizen is, by definition (and however unwillingly) a Leaver. So far so good. But then comes the first big logical fallacy. “Many of us now” introduces the argumentum ad populum, or a variant of it. In other words, while Parris is undoubtedly not alone in starting from the two premises he is about to outline, he at least implies that his view is common, and even shared by most Remainers. He provides no evidence for this.

And so to the two premises themselves:

Premise A is that because the people voted Leave in a referendum, Britain ought now to quit the European Union.

Premise B (former-Remainers insist) is that we must aim for a deal with our former EU partners that leaves Britain with many of the advantages of our one-time participation in the single market. Hardline Brexiteers call this “Brexit Lite”.

Premises are traditionally given numbers (and the terms within them letters), but I shall stick with A & B for the sake of clarity.

Premise A is not particularly problematic, although it is the conclusion of an implied argument establishing the force of democratic decisions. If pointing this out seems pernickety, then we might just note, in passing, that other great thinkers, such as Tim Farron, would reject even this premise.

Premise B is doing a lot of work and is really a number of premises in one. It is unhelpfully vague, it begs the question (petitio principii) and it finishes with a sly ad hominem. Let’s try to unpack it a bit.

First, there is at least an implication that “participation in the single market” is the most advantageous state of all for the UK. The qualification “many of” suggests this. This is where the begging of the question comes in. People often say that something “begs the question” when they want to say that it raises questions or demands answers, but here I am using it in its formal sense. Begging the question is where a conclusion, or another premise, is smuggled into an argument improperly. Here, the hidden premise is that the status quo ante (viz. our membership of the EU) was the best situation possible, and anything else will be less advantageous (to the UK, one assumes).

“Hardline Brexiteers call this Brexit Lite” is the argumentum ad hominem — the premise is rejected by the most thoroughgoing Brexit supporters as not really any kind of Brexit at all: “We Remainers are still right, and we’re still having to fight these idiotic Leavers!”

These are just niggles in comparison to what follows, though:

But Premise A is not consistent with Premise B. Assuming we should leave, maximum access to the single market cannot be the goal as it’s not as good as staying where we are. Assuming we want maximum access, we should not be leaving.

First, let’s be clear about what inconsistent premises actually look like. A simple example might be:

1. The Cat sat on the mat
2. The Cat did not sit on the mat.

Assuming we are talking about the same cat, at the same time, the same understanding of what it is to sit, and the same mat, both cannot be true. Interestingly, however, at least one premise must be true. If the cat sat on the chair or stood on the mat, then (2) is still true. This is not the case with Parris’s premises, which could both be untrue, from the point of view of simple logic.

Parris’s premises do not seem to be prima facie inconsistent, except in the sense that he may have smuggled into (B) his own prejudice — that the UK should not leave the EU. His argument, such as it is, is an odd one. The adjective “maximum” introduces yet more vagueness. One might say that “maximum access to the Single Market” is identical to “membership of the EU”, i.e that France has “maximum” access whereas Norway does not. But surely the qualification “outside the EU” is implied?

So, to paraphrase Parris’s argument, “Access to the single market cannot be a goal for the UK outside the EU because it is not as good as being inside the EU.” This value judgment masquerades as a conclusion, when in fact it is just another premise. So what we really have is this:

(A1) The British people voted in a referendum to leave the EU
(A2) The result of a legally held referendum should be respected

∴ (A3) Britain ought now to quit the European Union (A1, A2)

(B1) Former “Remainers” are mostly in agreement
(B2) Britain should aim for a deal with the EU that leaves Britain with many of the advantages of our one-time participation in the single market (SM)
((B3) Hardline Brexiteers call (B2) “Brexit Lite”)

(C1) Britain is currently participates the single market qua member of the EU (‘Maximum Access’)
(C2) Participation in the SM without membership of the EU is not ‘Maximum Access’
(C3) It is irrational to choose anything other than ‘Maximum Access’
∴ (C4) To leave the EU would be irrational (C1, C2, C3)

(D1) One should never pursue irrational ends.
∴ (D2) Britain should not leave the EU (B2, C2, C3, C4, D1)

This just about does the job. (A3) and (D2) are indeed inconsistent, or contradictory. But we should also be concerned about the validity of the argument, and whether it is a good argument. The argument as I have set it out is valid, but then so is this;

1. All cats can fly
2. Tigers are cats
∴ 3. Tigers can fly

This is perfectly valid, insofar as the conclusion proceeds from the premises, but it is also nonsense. For it to be a good (sound) argument, the premises also need to be true, and the problem for Parris is that quite a few of his premises are open to challenge. The most problematic is his insistence (apparently) that because Britain’s post-Brexit participation in the Single Market will be less ‘perfect’ than its pre-Brexit participation, then it should not be pursued as a goal at all. This is the premise which is both crucial to the argument and the most easily challenged as nonsense.

What Parris is doing is conflating the EU and the SM, and treating them as if they are the same thing. In this he is not alone, and Leavers are just as guilty as Remainers of this mistake. The EU is a political project of integration and conformity, and the SM is but one part of that. Norway participates in the SM as a member of Efta (The European Free Trade Association), Switzerland also has access to the SM, and is also a member of Efta, but does not have access in the way that Norway does.  European trade and cooperation is full of exceptions and peculiarities. The UK is (at the moment) a full member of the EU but not part of the Schengen Area, whereas Norway is part of Schengen from outside the EU. The UK has wisely resisted monetary union, whereas the Vatican City, which is not an EU member state, uses the Euro. There are territories within the EU Customs Union which are not EU members (e.g. Guernsey), and EU members outside the Customs Union (Gibraltar). One could go on.

Parris’s “all or nothing” ultimatum simply does not fit with the reality of Europe. What Parris seems to be saying is that the only access to or participation in the Single Market that is worthwhile is that which is automatic by virtue of having EU membership. Such a position is often held to be self-evident by Remainers due to the “Norway Solution” — as Parris puts it with characteristic smugness:

We rightly pointed out that countries outside the EU wanting the same access to the single market as those within it end up having to pay a subscription and then obeying rules they have little say in framing.

There are two problems which will be immediately obvious. The first is that this statement implies that EU members have “a lot of say in framing” the rules they must obey. This is a failure to understand the realities of international trade, where many supposed “EU Rules” actually come from international bodies such as UNECE. The second is that it ignores what many see as the benefits of being outside the EU (i.e. no longer members of the political institution).

Most estimates suggest that around just under 80% of the rights and obligations (acquis) that currently pertain to us as EU member state participants in the SM would not apply if we, like Norway, were members of the European Economic Area (EEA). Also, of that just over 20% of the acquis that would continue to apply, well over three-quarters come from international bodies where we would “have a say”.

Let’s suppose, though, that leaving the EU and joining Efta and then the EEA would cost us just as much as EU membership and give us no more and perhaps slightly less “say” than we currently enjoy. Could leaving the EU still be worthwhile? Many Brexiteers would say yes.

Even given that scenario, we would immediately gain a significant measure of freedom. We would take back control (yes, really) of our fisheries policy, agricultural policy and our criminal justice system. We would be free to make trade deals with non-EU countries all over the globe. We would not risk being drawn in to a future EU army, nor a bailout for yet another failure of the Euro. We would be able to set our own rates of tax without interference from Brussels.

Matthew Parris clearly believes that the EU is almost perfect. In other words, he must believe that there are many good things about it. However, he has also come to believe that the alternative to full membership must be a sour-grapes (or dog in the manger) rejection of everything connected with the EU (such as the single market). The choice is, and can only be, between the Devil (the EU) or the Deep Blue Sea (WTO Rules Hard Brexit). That is truly illogical.

Parris’s view is close to that held by a great many fearful and angry EU politicians, as well as a fair number of UKIP members who continually disparaged the “Norway Option” during the referendum campaign. As a piece of logic it makes no more sense than saying “If we are not at peace with Europe then we must be at war”. It is a false dichotomy. To leave the EU does not entail snubbing the EU, and it certainly does not demand that we reject any level of participation in the single market.

Parris seems now to be such an angry Remainer that he has transformed himself into a Hard Brexiteer. Perhaps that ought to tell us something about the danger posed by Hard Brexiteers?

He ends with a question:

With skill, judgment and luck Mrs May may finally achieve a decent compromise with Brussels, and get us something almost as good as what we had — and people like me will support it. But was it for this that Leavers voted Leave?

I can only answer for myself, but the answer is yes, a hundred times over.