21. It is more judicious not to suppose you know that of which you are in ignorance.
This is directed at those who offer criticism about matters unknown to them, even in basic terms. Plato completes this thought of Socrates by saying: "In first place, if it is possible, we must make them more honest in their words; if they are not, we shall not bother with them, and we shall seek nothing but the truth. We shall do our best to instruct them, but shall not insult them."
This is how Spiritism should proceed in relation to those who contradict, whether in good or bad faith. If Plato were to come alive today he would find things almost as they were in his time and he would be able to use the same words. Socrates would also meet creatures who would jeer at his belief in Spirits and would believe him to be mad, together with his disciple Plato. It was for having professed these principles that Socrates saw himself ridiculed, accused of impiety and condemned to drink hemlock. So, assuredly, by reason of its controversy stirring up many prejudices and striking against many prejudices, these great new truths will not be accepted without a fight, nor without making martyrs.