Rumsfeld is a bad epistemologist
Philosophy has a reputation for being largely irrelevant to the real world. That reputation is undeserved. Filmmaker Errol Morris inadvertently provides a nice illustration of why that is so in his recent documentary about former U. S. Secretary of Defense Donald Rumsfeld, “The Unknown Known“. While it might be common knowledge that Rumsfeld made some terrible decisions while at the Pentagon, it’s probably not common knowledge that he did so on account of being a terrible epistemologist.
First, Rumsfeld appeals (at 1:07:35) to the principle that ‘an absence of evidence is not evidence of absence’ in justifying the continued search for weapons of mass destruction in Iraq under Saddam Hussein. The principle appealed to is sound, since the fact that you’ve so far been unable to uncover any evidence that p, does not in itself entail that not-p. However, Rumsfeld’s appeal to the principle is not sound. There are situations where an inability to uncover evidence does constitute evidence of absence. For example:
Say that I can’t find my keys. If I’ve done a sufficiently exhaustive and thorough search through my desk drawer, I can reasonably infer from my inability to uncover any evidence of my keys in my drawer (an absence of evidence) that my keys are not in my drawer (evidence of absence). Or take a less trivial example: If competent enough people look for long enough, and still can’t find any evidence of WMD:s in Iraq, that’s evidence of there being no WMD:s in Iraq. Rumsfeld’s attempt to suggest otherwise is not only bad epistemology; it’s also sophistry.
Second, the title of Morris’s documentary is borrowed from something Rumsfeld writes in a memo (dated Feb. 4, 2004), which suggests that the unknown known corresponds to
(1) things you think you know, that it turns out you didn’t.
This makes very little sense. (1) doesn’t correspond to the ‘unknown known’, but to something far less philosophically sophisticated: being wrong. Moreover, given that Rumsfeld understands the known unknown in terms of things you know you don’t know (in the sense that implies an awareness of the limits of your knowledge), the unknown known would have to correspond to
(2) things you know that you don’t realise (i.e., know) you know.
When asked by Morris to explain the memo (at 1:32:55), Rumsfeld says something to the effect of (2). Morris points out that this is different from (1), i.e., the gloss given in the memo. Rumsfeld responds that Morris is probably “chasing the wrong rabbit”. But this is, of course, exactly the rabbit to chase. (2) doesn’t capture the intelligence situation at Pentagon under Rumsfeld. That situation is better captured by the gloss Rumsfeld should have given on (1): he was just plain wrong.
All of this provides a striking example of why philosophy matters, and why epistemology matters in particular. After all, had Rumsfeld been a better epistemologist, he might have (a) acknowledged that an absence of evidence sometimes makes for evidence of absence, and on that account hesitated to invade Iraq, or at the very least (b) looked back on his period at the Pentagon, and been able to acknowledge that he was just plain wrong.