"Ananda said to the buddha: 'I think there has never been a teacher as great as you, nor will there ever be one as great in the future!'
The buddha asked Ananda: 'Have you known all the buddhas of the past?'
'No, honored one,' responded Ananda.
'But you are able to know all the buddhas of the future, then?' asked the buddha.
'No, honored one,' Ananda repeated.
'Then I suppose you know my awakened mind completely?' the buddha asked.
'No, honored one. I do not even know your mind completely,' Ananda admitted.
'Then how can you make such a bold statement as that I am the greatest teacher that ever was or will be? It is much better to talk of what you know than to speculate foolishly,' the buddha told Ananda."
This exchange from the Majjhima Nikaya it a good one to keep in mind when we find ourselves so sure of our perceptions and opinions. We often seem so sure of ourselves when we impute motivations to others; and we can pontificate on the subjects we have very little experience in as if we have the deepest insight into them. This passage reminds us to be a bit more humble in regards to the confidence we hold for our perceptions and opinions.
The fourth precept includes this understanding, not to speak of things of which we are not sure, but there are actually very few things of which we are sure! Ananda says he does not know the buddha's mind completely, but truly, there is no one among us who can say we know our own mind completely! Both neuro-science and cognitive science shows us that much of what we do and think we think is guided by the unconscious and pre-conscious mind to which we have no access. We do things and then confabulate reasons. Perhaps only children, who openly admit they do not know why they've done something when asked why they've done it are completely honest. Bodhidharma, when asked by Emperor Wu, "Who are you?" responded "I don't know."
If we too can remember that we often do not know, perhaps we can stay more intimate with our experience, maintaining an ardent sense of curiosity while holding a relaxed grasp on our perceptions and opinions? But we do love to speculate, don't we? Perhaps this exchange can help us remember to speculate wisely, rather than foolishly assert things to be that we truly have little to no idea about!
"Appropriate thinking" is the second of the 8-limbs of the buddha's eight-fold path. One actual practice to support appropriate thinking is to ask oneself: "Am I sure?" when we find ourselves asserting something as fact. And when we catch ourselves indulging in the idea gossip of speculation, we can stop ourselves and kindly ask ourselves: "What are you doing?" Finally, when we see we've given sway to foolish speculation -- especially as to the motivations of other's behavior, we can say to ourselves, "Hello habit energy!"