Everyone is entitled to their own opinion.

( Posted on my Facebook page, An Idiot Talks. )

"Everyone is entitled to their own opinion."

If you've ever seen or been in a debate, on or offline, you've heard this phrase quite a bit.  The people who say it are right, you know.  You do have a right to your opinion, same as everyone else.  However, the context in which they use it is often wrong.  People who say this often seem to think all opinions are equally valid, and will say such a thing in debates on topics where opinion plays no part.

On issues like global warming, same sex marriage, abortion, genetically modified organisms, and a variety of other topics, people will claim that everyone is entitled to their opinion, and they will use this to shoe in their opinion, no matter how ill informed. They will indirectly make the argument that because they have the right to an opinion, they have the right to have their opinion taken seriously on any and every topic.

On certain subjects, such as which music genre you prefer, one opinion is as valid as another.  Others will disagree with your choice in music, but there’s no objective way to decide how we decide what is good and bad.  I personally find rap extremely distasteful, for instance, but that doesn't invalidate your personal preference.  There is no right or wrong style of music.  We can arbitrarily pick a way to measure good music against bad -- complexity or simplicity of formal design, chord progressions, or melody, for example.  We can then decide that based on these criteria, this song is better than that one.  But this in no way invalidates personal preference, which is the reason any of us listens to music in the first place.  So what we like is what we like, and by definition, is better than what we don’t like.  For us.  It is entirely different for someone else with different sensibilities.  This is the nature of subjective judgement.  There’s no consistent method for choosing a right and wrong answer.

Things are different on *objective* subjects.  On subjects like preferred music genre, your opinion is as valid as anyone else's.  On subjects like math, on the other hand, your opinion is irrelevant if it is demonstrably incorrect:

2 plus 2 will always equal 4, even if your personal opinion says otherwise.

Math and science are objective.  They have no room for subjectivity, and thus personal opinion doesn't play any role in the answer, as much as we'd like to believe otherwise.

In every field of science we strive to remove subjectivity as much as possible.  You can see this in the very strict rules about acceptable methodologies, in the absolute requirement for reproduction, in the requirement for peer review, in the requirement for thorough cataloguing of all variables, of all controls, of all conditions.

When debating things like global warming, birth control, abortion, same sex marriage, minimum wage, and any number of other topics relating to economics, social issues, and science, the evidence is sound, and your opinion, indeed any opinion including my own, has no place in the subject.  All that matters on the subject is the evidence, and in all of these topics there is conclusive evidence which renders a large number of common opinions dead wrong.

This isn’t to say you can not challenge scientific consensus on a topic by any stretch of the imagination.  You are more than welcome to.  However, you can’t challenge it merely on the basis that you disagree with it, or your religion disagrees with it, or other such subjective observations.  To challenge it, you need to gather evidence, design tests, analyze the data, and pass these procedures through rigorous tests for objective accuracy.  In other words, you need to do science.  

This isn’t always an easy task, but it is possible for even the average layman to do.  With a good understanding of the scientific method, research design, and statistical analysis, it is possible to find flaws with existing research which call the results into question.  In effect, this is what peer review does.  It’s not always perfect, but in the long run, it almost always catches its mistakes.  Sometimes non-scientists call attention to a problem.  In some circumstances, laymen can even conduct their own experiments.  But again, they must include the same rigorous standards of evidence and replicability as if they were working for a university.