“What can happen to great thinkers when their ideas are critical of others?”

This can lead to, if the other person's idea is more popular or the other person themself is, the great thinker being discredited and/or disliked. Such as if someone said a very popular food was poisonous, but someone else said it wasn't, people might believe the latter person's idea, as they don't want the other to be true possibly. It can also possibly have the reverse effect of the person with the other idea being discredited and/or disliked. If the great think is known for being a great thinker, people might then think anyone who disagrees with them must be wrong and possibly even foolish or something. It also may lead to it being harder for people to realize when the great thinker is wrong because they might have already thought of how they must be right and started thinking that the other was clearly wrong because of that, which might dissuade them from realizing they were actually wrong and that the great thinker had made the mistake. This may also apply if both are correct, but people think the great thinker is *more* correct.

it is about the use of non animal tested cosmetics.