Do y'all think prophets believe/think they are receiving inspiration when they pray for it, and speak as prophets in an official capacity?
If so, then it seems clear, based on the fact that they are often wrong, they are unable to discern what is or is not inspiration.
A veritable clinic in logical fallacy construction.
The first sentence implies a missing premise, that would, given TD's conclusion, be something alone the lines of "if prophets receive revelation, then they will always know when and if they are receiving it".
Since, she says, "they are often wrong", it follows that "they are unable to discern what is or is not inspiration". An alternative first premise might be "If prophets receive revelation, prophets will always be right".
Hence we have:
If prophets receive revelation, then prophets will always be right."
Prophet's are often wrong.
Therefore, prophets are unable to discern what is or is not inspiration.
In analyzing TD's argument, what do we see? First of all, the first premise makes a statement that is nothing but a bare assumption. Do we always know when the Spirit is working with us to frame and articulate ideas? What makes TD think so? Have the GA's taught that this is the case?
The real problem, however, lies with the second premise. Now, it is not that TD claims (without examples), that prophets are "often wrong". The problem is an unstated assumption that every word that comes out of a prophet's mouth should be an inspired word, and hence, any time a prophet is wrong, we are justified in questioning his claim to inspiration.
All well and good, until one realizes that neither Joseph Smith nor anyone since him has ever taught that a Prophet, even when discoursing on religious subjects, is by any means continually and constantly inspired. Indeed, Joseph taught precisely the opposite. Indeed, once one realizes (a realization that TD and Beastie are tying with all their heart, might, mind and strength to avoid) that when prophets are wrong, they are wrong because human beings are often wrong and for no other reason, this entire argument shatters like the brittle piece of crystal it is. No one is saying that prophets, as men, cannot be wrong. No, they cannot be wrong when, in acting in the capacity of their calling and office, when they receive the mind and will of the Lord, but here TD makes yet another circular assumption, assuming what she has yet to demonstrate, which is in essence, that they don't receive that mind and will of the Lord in any event.
She however, does not know that they do not, and hence, pointing out where a man who happens to be a prophet can, on occasion, be wrong, is little more than a pedestrian observation of little import from an LDS point of view.
It looms very large indeed, however, in Babylon and its suburbs.
In the end, the argument appears to be an inductive argument masquerading as a deductive one. Its interesting because TD appears to be leaving the possibility open that revelation exists and can be received, but that most, if not all prophets, are incapable of knowing when and if this is happening, which is even more interesting because this implies that, even if revelation does exist, its essentially useless to human beings, since it cannot be discerned with any accuracy.
The inferential leap, that "prophets are unable to discern what is or is not inspiration", is a weak one, for the reason that that leap relies upon a fusion of the calling or office of prophet with the human being who holds that office such that the two become identified. It now becomes possible to claim that every opinion one who holds the calling has on anything from theology, to politics, to educational theory, if it can be shown to be less than credible, is a reflection on his prophetic calling.
The logical weakness of TD's argument now becomes clear. If prophets can also be human beings, then they can be wrong on occasion, and the entire artificial edifice tumbles to the ground.