Is science really as neutral and objective as scientists claim? Let me for arguments sake use the example of "ghosts". When a person lives in a country with wide-spread belief in the supernatural they are more likely to interpret a strange event as having a supernatural component. We can say that they are not analysing the event in an objective way, but are interpreting it from the biased mindset that "the supernatural exists". A scientist looking at the same event would not have such cultural assumptions; but he is interpreting the event on the basis of what he already knows about science (ex, That cognitive processes have a biological basis, that immaterial beings violate the laws of physics as they are currently understood, etc.) Now we know from history that many scientific theories which had the support of the entire scientific community turn out to inconsistent with empirical observation in some way and require modification or to be discarded entirely. Similarly, some theories which were once considered wacky (ex. string theory) go on to gain more support in the scientific community.
So the scientist interprets the same event from a mindset which (according to sheer probability) has at least some erroneous assumptions. Can we really say his perspective is completely neutral and objective?