I just came across a rather startling remark made by Protestant theologian Cornelius Van Til:
The law of contradiction, as we know it, is but the expression on a created level of the internal coherence of God’s nature. Christians should therefore never appeal to the law of contradiction as something that, as such, determines what can or cannot be true. [Introduction to Systematic Theology, 11]
Many years ago I read that book. It has been far too long for me to remember anything in particular about it, but I must confess that I find this to be a rather bizarre remark, and likewise one that is just wrong.
In the first place, the law of contradiction is first and foremost a comment on the nature of existence, and it wasn’t formulated by a Christian. It’s as old as the Greeks. It’s as simple as this: whatever is, is; whatever isn’t, isn’t. A thing can’t exist and not exist at the same time. You don’t have to be a Christian to realize this. It’s bound up in the very meaning of the terms.
In the second place, I can’t fathom how anyone could rationally say that the law of contradiction doesn’t say anything about what can or can’t be true. The keyboard I’m using either exists or it doesn’t, and to say that the law of contradiction doesn’t determine this is utter nonsense. Likewise a given geometric shape is either a circle or it isn’t. It can’t be both a circle and a non-circle at the same time and in the same respect. So to say (as Van Til apparently did) that the law of contradiction must not at all be appealed to as a determiner of what’s true is crazy talk.