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.