What does allow scientist to make moral and ethical judgements? I always thought that science is purely neutral and objective(yes I know this is an illusion, even if we destroy all bias and all string pullers(government, private/commercial sector) still even scientists unconsciousness can make the objectivity of his work biased without him even being aware of it), yet I see scientists making moral and ethical(which seem purely subjective to me[based on belief or opinion]) judgements nearly everywhere...

You ask a very good question! Much depends here on (first) how one defines 'objectivity' and (second) what objectivity might mean in the case of science and (third) the standing of moral beliefs.

Objectivity has lots of possible senses - e.g. being free from biases and prejudices, or being impartial and 'non-subjective', and so on - and it's not clear which of these senses of objectivity are defensible, and not clear either how they feature within science (for instance, perhaps scientists only need to be objective in a particular sense at a particular point in their research, such as its practical application). There is a very good history of the concept of objectivity by Lorraine Daston and Peter Galison called 'Objectivity' - beautiful but a little pricey - which explores three of the main senses of objectivity in the recent history of science.

The standing of moral beliefs - whether they are or can be 'objective' or whether they are merely belief and opinion - is both easier and harder. Easier because moral and ethical judgments and claims aren't just belief or opinion for the reason that arguments can be given for them (that's the business of moral philosophy!) and it is the provision of argument that raises a mere opinion into a substantive position, something worth taking seriously. Harder because providing philosophical arguments for our moral beliefs is, of course, difficult -- but that's not to say that our moral beliefs are just opinion.

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