via Brad: Roger Olson has an excellent discussion of mystery, paradox and contradiction here.
"A mystery is one thing; a paradox is a closely related thing; a logical contradiction is something else entirely. Here I agree entirely with Reformed theologian R. C. Sproul (Chosen by God, pp. 46-47). God is transcendent and therefore will always be mysterious to us. Mystery results in paradox because God is transcendent and we are finite and fallen. But contradiction is something even God cannot embrace because to embrace it is to fall into complete incoherence and unintelligibility...."
Olson then goes on to discuss a contradiction he sees in Calvinist theologies:
"...Now, to the point. Do some theological systems include contradictions? I believe so. They are almost always unrecognized and/or unadmitted. Sometimes they have to be ferreted out by careful examination and argumentation. When it can be shown conclusively that two elements of a system actually do contradict each other the system must change to accommodate that. And I cannot embrace a system that contains unresolved and unresolvable logical contradictions. (I may agree with parts of such a system, but I cannot swallow it whole.)
If even one logical contradiction can be identified at the heart of a theological system that is a fatal flaw for the system itself. At that point the system must be radically revised or given up and replaced with a different system.
I have identified here and elsewhere what I believe to be a fatal flaw in SOME Calvinist systems of belief. That is, insofar as a person believes that God foreordains and renders certain everything without exception FOR HIS GLORY and also believes that heresy (for example) diminishes or reduces God’s glory by robbing God of some of his glory he falls into contradiction. Both beliefs cannot be held at the same time. It is not a case of ordinary paradox–apparent contradiction. It is a case of sheer, unresolved and probably unresolvable logical contradiction. That is why, I believe, no Calvinist has ever risen to my challenge to explain it.
Every Calvinist that I know (and I don’t know them all) says that some beliefs (e.g., panentheism) detract from God’s glory and that is why we must oppose them with all our (persuasive) might. They diminish and detract from God’s glory. They dishonor God. They rob him of glory. Every Calvinist I know also says (usually elsewhere in his or her book or article or sermon or whatever) that God foreordains everything without exception FOR HIS GLORY.
Now some Calvinists might take the approach that panentheism (for example) does not really, ontically rob God of glory as that is impossible for any creature to do, but it diminishes recognition and acknowledgement of God’s glory in the minds of its believers. But, so what? God foreordained that also-for his glory. That a panentheist is a panentheist was foreordained and rendered certain by God for his glory (according to the Calvinists I know).
It also won’t work to say that God foreordained panentheism so that he could overcome it and by revealing it as false glorify himself. Even then, the existence of panentheism, if determined by God to redound to his glory when he overcomes it, in the meantime glorifies God insofar as it is decided by God as the means to that end.
For the life of me I cannot figure out why Calvinists of my acquaintance do not see this as a sheer logical contradiction and move to resolve it. I have asked many about this issue and they have always just looked at me as if they never thought of it or they rely on some version of an answer I just mentioned above which are no answers at all.
All that is to say, one reason I am not a Calvinist is that to be one I would have to sacrifice my intellect IN THE STRONG SENSE of embrace sheer logical incoherence and unintelligibility. NOT IN THE SENSE of embrace mystery with which I have no absolute problem. I believe this is a fatal flaw in so-called “consistent Calvinism” (which, in light of this flaw, is really “inconsistent, consistent Calvinism!).