In late 1943, the German High Command know that the build-up of US troops in England makes invasion inevitable. It's just a question of where and when.
This is testing the application of argumentation to Analysis of Competing Hypotheses (ACH), using the WW2 operation Fortitude South as an example.
Following the method...
In late 1943, the German High Command know that the build-up of US troops in England makes invasion inevitable. It's just a question of where and when.
See here for list of hypotheses, and some rationale for selecting two to take forward.
See here for list of information, we'll use as evidence in assessing hypotheses. This is a working document that we can modify and extend as we go.
See here for the initial matrix.
It's not the existence of the army groups FUSAG and 21AG that is diagnostic, but their location: FUSAGLOC and 21AGLOC. SIGINT and RECON serve only to determine the locations of the army groups, so could be considered subordinate arguments already accounted for by FUSAGLOC and 21AGLOC. Similarly, PATTON serves only to identify FUSAG as the primary invasion force, so is also subordinate to FUSAGLOC. We can collect all these items of evidence together under the single heading: Order of Battle (ORBAT). This will be consistent with Pas de Calais and inconsistent with Normandy, and we need to capture the subordinate argument justifying that conclusion.
We can categorize the lines of evidence according to the types of presumptive reasoning used, that is to say their argumentation schemes. We might also then collect together lines of evidence by argumentation scheme. For example: SHORTEST, STRONGPOINT, EXPANSION and VSITES are all Argument from Consequences. It might be instructive to consider these in isolation and "weigh up" the consequences. If we do this, we can see that there is no clear answer from just an assessment of consequences. However, we might decide that the key opposing arguments are STRONGPOINT and SHORTEST. VSITES seems relatively trivial by comparison, and we might decide at this stage to consciously ignore it. EXPANSION probably also carries much less weight than STRONGPOINT and SHORTEST, but we may decide to leave it on the table anyway.
See here for the refined matrix.
This now includes ORBAT, as discussed in the previous step. VSITES has been removed as it is considered unimportant, and we add another item to the information list to record this decision.
On the face of it, Pas de Calais seems the much more likely option.
The method says to proceed by disproving rather than proving hypothesis. There isn't anything we can clearly disprove a this stage, but if we had carried forward all the hypotheses from step 1, we might reasonably reduce the list to just two at this step.
This is also the point at which to consider how much weight to put on individual items of evidence when considering the likelihood of a hypothesis. We have no indication of strength of consistency or inconsistency in our matrix (just a single plus or minus) - but various schemes can be imagined...
ORBAT is probably the most critical; but this is a conclusion based on a number of other items of evidence that consistently support each other, and it is backed up by SPIES and AIRPLAN. STRONGPOINT and SHORTEST are incontrovertible, and PORT is a seemingly sound logisitical judgement.
This step in the process is the point at which Heur suggests you consider denial and deception. As things stand, this analysis represents the Axis view of the world. However, Fortitude South was a deception operation, so we can equally cast this as the Allied model of the Axis view of the world - put together as part of a deception plan.
This is about conveying a balanced judgement to decision makers. Something like the Toulmin model of argument might be useful here, as it allows a concise expression of facts and a qualified conclusion, and affords the opportunity to question how the conclusion was reached. In other words, it supports explanation.
For this example, the future observations are just those that are the normal business of military intelligence. However, it's one thing to record what new observations would make you change your mind, and another thing to be alert to those events when they happen, and trace them back to your original analysis. This is where recording information as linked data has benefits.