 However, Dretske (1986) sees a problem with this starting idea. He illustrates the problem with the case of ocean-dwelling anaerobic bacteria that have tiny magnets (magnetosomes) that are attracted to magnetic north, which serve to direct the bacteria downwards into the relatively oxygen-free sediment on the ocean floor . Plausibly, the function of the magnetosomes is to direct the bacteria to anaerobic conditions. If we “fool” the bacteria by holding a bar magnet nearby and lead the bacteria upward to their death, this looks like a case of natural misrepresentation. We were, in Dretske’s words, looking for “nature’s way of making a mistake” and we seem to have found it. The problem, says Dretske, is that it is indeterminate how we should describe the function of the magnetosomes. We can plausibly say that they have the function of indicating the oxygen-free sediment. But we can also plausibly say that they have the function of indicating geo-magnetic or even local magnetic north. If we say the latter, no misrepresentation has occurred. So Dretske’s interim conclusion is that we cannot count this as an unambiguous case of error, on his theory as outlined so far.