Brown Moses is under attack for having failed to reveal a conversation with Matthew Van Dyke. In this conversation, Van Dyke says the following (verbatim extracts):
don't rule out the possibility that the rebels do have a small quantity of chemical weapons. I've had information for a few months on this
I have a source that has been reliable in the past, who gave me information about the rebels having acquired a small quantity a few months ago, and I know what building they came out of. and I know some things about the building, having been to the site, that give the information some additional credibility.
I think it was a small quantity, judging by where they were stored but by small quantity, I mean possibly hundreds of shells of some type. I do not know. The source didn't have that level of detail.
It is said that the failure to report this conversation damages Brown Moses' credibility. It does not. Whether or not Brown Moses should have reported the conversation for some other reason, his credibility is not at issue.
What is Brown Moses credible about? He is not a reporter. He is not a witness. He looks at thousands of reports, and analyses them. His credibility stems from the caution with which he comes to conclusions and the meticulous care with which he evaluates the testimony - in a number of media - of others.
What is involved in the process of evaluation? It involves discarding many hundreds of reports as unreliable or irrelevant. In his analyses, of course, he does not repeat the vast majority of these unreliable reports: only in rare cases, where a report is thought by others to have credibility, might he report them, to offer reasons why this is not the case.
Where chemical weapons are involved, most of the reports discarded by Brown Moses, and most of the reports he discredits, have attributed the use of chemical weapons to the Assad regime. In some cases it now seems that these reports may have been correct: subsequent information has made them more plausible. So it is hardly the case that his sorting of reports has exhibited anti-Assad bias.
The conversation with Matt Van Dyke fits into this pattern. I myself have seen many reports - a tiny fraction of what Brown Moses has examined - where all sorts of things are called chemical weapons which are anything but. There are, for example, kits which test for chemical weapons. There are also cases where riot gas, phosphorous shells and other munitions have been called chemical weapons, but which are not considered chemical weapons by specialists, and which could not be implicated in the notorious Sarin attacks whose examination is associated with Brown Moses' work. ('Chemical weapons' is typical of the broad, inaccurate descriptions ubiquitous in Syria reports. Any fighter plane may be called a 'MIG'; armored personal carriers and self-propelled guns are called 'tanks'; any large surface-to-surface missile becomes a SCUD.)
Consider, in this context, the conversation with Matt Van Dyke. First, he has not seen any chemical weapons, nor does he claim to have seen them. He claims to have been 'given information' that the rebels have them. The information is said to come from 'a source that has been reliable in the past'. But about what? Presumably this someone is not a chemical weapons specialist, but simply someone who has talked to Van Dyke in the past, about other events. Considering that the mis-characterization of munitions as 'chemical weapons' has been more the rule than the exception, this matters.
But wait! Van Dyke does not say that his source claims to have seen any weapons. He has been 'given information'. This could mean that his source has seen them, but also that he talked to someone who has seen them or, for all we know, talked to someone who talked to someone who has seen them. All we know for sure is that someone is said to have seen them - possibly the reliable source, possibly not.
Now what of Van Dyke himself? Is he a credible, authoritative source? I personally might trust him, but the answer is that he can't be judged either credible nor not credible. He has made short documentary films and also characterizes himself as a freelance journalist. But his reporting experience is very limited and he has never been subject to the sort of professional scrutiny that career journalists normally undergo. So despite my own tendency to believe him, he cannot be considered an established credible source in journalistic terms. He's not, let's say, Ben Wedeman of CNN. (I won't even consider the question of how Brown_Moses was supposed to know he really was speaking to Matt Van Dyke, not a malicious impostor.)
What's the upshot? We have one of hundreds of reports of 'chemical weapons', an expression we know is habitually used to describe munitions that are not, in fact, chemical weapons. The source of this report is an un-named party who quite possibly is recounting what he heard from another un-named party. The person who reports this report is Matthew Van Dyke, a nice guy but whose credibility has not been established. We might also wonder how the munitions were identified as munitions actually loaded with a chemical agent, as opposed to munitions capable of containing such an agent, or its precursors. Did someone have a sniff?
That's not all. In the conversation, Brown Moses undertakes not to reveal that this report comes from Matthew Van Dyke. So Brown Moses would have to report that an un-named and not authoritative source claimed that an unnamed source, claimed to be credible, either claimed that he had seen chemical weapons, or claimed that someone else claimed to have seen them - in some undefined sense of 'chemical weapons' and even of 'seen'.
What sort of weight would Brown Moses' report itself carry? Would this take its place among the eyewitness testimony, the on-the-ground reports of UN chemical weapons specialists, the videos minutely analysed by munitions and by many media specialists? To answer yes would not, I think, be credible.