This is a very important point and raises the question that interpretivists would pose -- can *any* research really be (completely) objective? For example, how do positivists decide what to research? Interpretivists would argue that already this decision inherently involve value judgements, not to mention all other decisions about how the research is conducted. I think these days it's much more common for scientists to identify as post-positivists, relaxing these strict requirements and attempting to minimise biases but still attempting to find generally applicable "laws".