  A recent Science paper (Bushdid et al, 2014)[1] proposed that humans can
discriminate between at least a trillion olfactory stimuli. Here we show that
this claim is the result of a fragile estimation framework capable of producing
nearly any result from the reported data, including values tens of orders of
magnitude larger or smaller than the one originally reported in [1]. We
conclude that there is no evidence for the original claim.
