It was, of course, Socrates who (according to his student Plato at least) said that “The unexamined life is not worth living.” From what we know of him, he might well have also said: “The unexamined opinion is not worth holding.”
Socrates had the annoying habit of asking questions of people, especially challenging them to question their unexamined opinions. It did not make him popular. In fact, he was sentenced to death for it.
I haven’t been sentenced to death yet, but I have, often, been sentenced to silence when in polite company. When I hear an opinion expressed that shows signs of not having been sufficiently thought through, I cannot resist embarking upon an examination of the opinion. I pose questions, inviting the opinion holder to elaborate and defend their opinion. Partly this is for my own sake, trying to understand what their meaning is, but also, I must confess, I embark upon this interrogation out of compassion and concern for the one who has expressed the half-baked, barely thought-through opinion, in the hope that we might together proceed to a point of agreement on what the actual case may be.
I usually receive one or both of the following reactions:
1) Everyone is/I am entitled to their/my own opinion.
2) I don’t have to justify myself to you.
Both these protestatations are, of course, quite correct. BUT, I would say, in answer to (1) no-one is entitled to hold an opinion for which there is no justification, and (2) you have to be able to justify your opinion to yourself and (if you have a religious conscience) God. If you are able to justify your opinions to yourself before God, then you ought also to be able to justify your opinion to anyone who asks you to give an account of it. You are entitled to your own opinion only in so far as you are able to defend it. If, upon examination, you find that your opinion cannot be justified, you ought (in good conscience) to give it up, or at least to adapt it.
Thus, if you were to say “Life only begins at 14 days after birth”, I would expect you to be able to argue the point. Not because I have a right to hear your justification for this odd opinion, but because you yourself need to be able to justify it to yourself (and the aforementioned deity whom you may or may not belive in). Further, when I justify my opinion “that life begins at conception”, I am duty bound to be able to justify this assertion. In making that justification, I am not trying to “force my opinions onto you”, rather, I am attempting to show that the opinion is rational and has merit.
If you disagree with me, then I would expect you to do me the honour of pointing out where I have gone wrong in my opinion. Conversely, when I point out the possible errors in your own reasoning, I am doing you the honour of taking you and your opinions seriously enough to engage them.
I would expect that you would treat yourself with equal honour and examine all your own precious opinions in the light of the available data and the application of rational argument.
Yes, everyone is entitled to thier own opinion. But you are not entitled to an opinion which you have not even bothered to thoroughly examine or which you refuse to examine when challenged.