"When is it a better idea to refrain from telling the truth?" As with every situation, it is crucial to look at all perspectives. In thsi example, it is important to consider the other person.
My answer is: refrain from telling the truth if doing so produces more harm than benefit for the other person. For instance, if you think your friend asks you 'najin do you think im ugly?' but you really do think she is ugly. You SHOULD NOT tell her 'yes dear, I think you are ugly'. Telling her so does nothing to improve her self esteem, doesnt do YOU any good and doesnt do her any good. There is nothing heroic about sticking to a core moral principle of 'never lie' or any other moral principle, if the end result is harmful.
Ofcourse, what 'you' perceive to be harmful or not is subjective. For instance, if your friend tells you she is going to start smoking btu you know that telling her the truth about smoking will offend her and she will feel anxious, depressed, etc. In THAT case I believe you shoudl tell her, at the risk of offfending her because in the long run, cessation of smoking will produce more benefit than offending her would harm, by comparison.
But to simply stick to 'tell the truth at all costs' is unproductive and potentially harmful. Adding to that, it is somewhat inconsiderate, as you may harming someone else in order to adhere to your own moral values.
Afterall, what is the purpose of moral principles? Lets not argue about god's commands and laws (because once god is brought into the picture there cannot be any discussion). The purpose of moral principles is to produce stability and cooperative existence in members of a society. We dont kill because that produces an unstable soeciety. We dont steal for the same reason. We dont rape for the same reason. If telling the truth produces instability (even small such as hurtihng someones feelings), then it is no good.
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