Tag: logic

Step Away from the Category

I recently stumbled across an interesting blog dedicated to the union of the Christian Church, an admirable goal. But being always on the lookout for sloppy logic, I noticed one article in which the author attempts to show that:

Within Protestantism there is not some one additional entity to which the term “visible catholic Church” refers, consisting of these denominations, congregations, believers and their children.

As opposed to the one entity which is the Roman Catholic Church, of course.

Unfortunately, the only thing the author shows is that philosophy students should be forced, at gunpoint if necessary, to take a formal course in logic before they graduate.

His argument is as follows:

This was the error of assuming that unity of type is sufficient for unity of composition. In actuality, things of the same type do not by that very fact compose a unified whole.

At first glance this might suffice for a Platonist, but consider this: who gets to decide which collections of things of the same type get their own unified whole, and which don’t?

If the Westminster Confession defines the “visible catholic Church” as the unity of Protestant Christians, then who is the author to claim that that entity does not exist, whilst the entity known as the Roman Catholic Church does?

I assume that the author would assert that the doctrines of the Roman Catholic church hold more authority than the Westminster Confession. But this is not an argument, it is an axiom: he has not “shown” anything, but simply restated his underlying assumption.

I can, in fact, refute his argument by construction.

Consider the set C, defined as the set of persons adhering to a Christian tradition descended from those developed in the Protestant Reformation.

If mathematics has any access at all to the world of Platonic ideals, then I have just shown that there exists, both in our world and in the ideal world, an entity, C, which is identical to the “visible catholic Church” as defined in the Westminster Confession.

Quod Erat Demonstrandum

John Piper is an Idiot

Suzanne McCarthy ably documents some recent failures of common sense, Christian charity and just plain logic on Piper’s part.

However, I have known this for a long time.

I wrote a review over ten years ago of his Desiring God, a book which attempts to encourage what Piper calls “Christian hedonism”. The concept is as bemusing as I write this as it was then, but bear with me, because the book begins with a plainly fallacious argument.

In the first chapter, he attempts to found his entire enterprise on the notion that the proper end of humankind is happiness. A bit dubious, to my mind, but certainly a valid opinion. Why should happiness be the ultimate goal? Because God is happy, of course.

The idea that God partakes of a mental state influenced by waves of ions and streams of neurotransmitters in a neural network is a bit wierd to me, but let’s accept that as a given, because Piper is setting up a formal argument. He says that he can show that God is happy by the following argument:

    If God were not sovereign, She would not be happy.

This axiom seems even more dubious to me, but let’s give Piper the benefit of the doubt one more time.

    We assume that God is sovereign, therefore God must be happy.

This is a completely invalid argument. Even if its axioms were individually true, the form of the argument itself guarantees that we can have absolutely no knowledge of whether the conclusion is true or not.

In formal logic, it’s called denying the antecedent, and is one of the classic blunders.

Let us try a different argument with the same form:

    If I were not human, I would not be Japanese.
    I am human.
    Therefore, I am Japanese.

It is obvious from this example that the argument proves nothing at all about whether or not I am Japanese or whether God is happy.

From this incoherent starting point, the book proceeds to pile shoddy reasoning upon linguistic ignorance to eventually completely re-define the word “hedonism” to mean a sort of grim Sisyphean death-march towards the kind of lifeless legalism to which Piper is evidently dedicated.

Nothing has changed, it seems.