Another reason for a loss of confidence in Big Data is that it does not deal in absolute but instead produces what Sicular describes as “a proof of your hypothesis with a certain degree of confidence” rather than a concrete answer.
Obviously, since that's what every discovery process does. Even tautological ones (those that only involve the manipulation of formal abstractions, ie mathematics) are only "proofs" under axiomatic assumptions about such things as the proper functioning of the reasoning mind.
So, welcome to Bayesian reasoning, Gartner. Glad to see you could make it.
 This is Descartes' "evil genius" argument: you can't prove that there isn't some "evil genius" with the capacity to force you to believe erroneously that some construction is logically valid. These days, neurobiologists are pretty close to constructing real tools to achieve that, between pharmacological agents and EM manipulation of CNS processes, coupled with the use of functional MRI to determine when and where to apply the tech. Experimenters have already shown they can erase (or render inaccessible) a subject's memory of a specific event, for example.