How does a mindfulness practitioner use judgment? I don't know if that is clear about how to judge or not judge in the Eightfold Path. Is it not clear because different Buddhisms disagree?
How does a mindfulness practitioner use judgment?
Is an intention/action skillful or unskillful? Does an intention/action increase or decrease distance to Nibbana?
Is the intention in line with the Factor of Right Intention, found in The Noble Eightfold Path?
These are examples of the use of judgement.
Knowing judgment, a mindful practitioner knows judgment as being a mere fabrication ... not truth.
Knowing this, he uses his judgment only as a vehicle which other beings can use to advance on their paths towards realizing the truth.
How does he use his judgment?
Every judgment he makes, is based on visible facts ... not truths, which to beings not yet liberated, look like truths.
Without knowing these facts, he does not judge until he knows these facts.
Once the facts are known, they are presented in such a way as if a vehicle was given by which one can advance on the path towards the realization of the truth.
Each factor of the Noble Eightfold Path is related to the use of 'judgment' or 'clear comprehension' ('sampajanna'), except the last factor of Right Concentration, which is the result of right judgment.
Right View is the guide for judgment. By the judgment of Right View, the wholesome categories of Right Thought, Right Speech, Right Action & Right Livelihood are established (and the wrong path is rejected). MN 117 states:
Of those, right view is the forerunner. And how is right view the forerunner? One discerns wrong view as wrong view, and right view as right view. This is one's right view.
Right Effort uses the judgment of Right Mindfulness-&-Clear-Comprehension to prevent & abandon obstacles to Right Concentration & develop the factors that generate Right Concentration. MN 117 states:
Now what, monks, is noble right concentration with its supports & requisite conditions? Any singleness of mind equipped with these seven factors — right view, right resolve, right speech, right action, right livelihood, right effort, & right mindfulness — is called noble right concentration with its supports & requisite conditions.
One makes an effort for the abandoning of wrong view & for entering into right view: This is one's right effort. One is mindful to abandon wrong view & to enter & remain in right view: This is one's right mindfulness. Thus these three qualities — right view, right effort, & right mindfulness — run & circle around right view.
When judgment (clear comprehension) & mindfulness work together, the mind can be established in the non-judgment of Right Concentration. MN 117 states:
Of those, right view is the forerunner. And how is right view the forerunner? In one of right view, right resolve comes into being. In one of right resolve, right speech comes into being. In one of right speech, right action... In one of right action, right livelihood... In one of right livelihood, right effort... In one of right effort, right mindfulness... In one of right mindfulness, right concentration... In one of right concentration, right knowledge... In one of right knowledge, right release comes into being. Thus the learner is endowed with eight factors, and the arahant with ten.
When Right Concentration is reached, mindfulness & clear-comprehension must judge that the mind is in a state of non-judgmentalness.
MN 117 describes how mindfulness is used to judge:
One is mindful to abandon wrong view & to enter & remain in right view: This is one's right mindfulness.
One is mindful to abandon wrong resolve & to enter & remain in right resolve: This is one's right mindfulness.
One is mindful to abandon wrong action & to enter & remain in right action: This is one's right mindfulness.
The Dhammapada also mentions the importance of right judgment:
316. Those who are ashamed of what they should not be ashamed of, and are not ashamed of what they should be ashamed of — upholding false views, they go to states of woe.
317. Those who see something to fear where there is nothing to fear, and see nothing to fear where there is something to fear — upholding false views, they go to states of woe.
318. Those who imagine evil where there is none, and do not see evil where it is — upholding false views, they go to states of woe.
319. Those who discern the wrong as wrong and the right as right — upholding right views, they go to realms of bliss.
A good new Essay on this topic, by Bhante Thanissaro:
Wisdom over Justice An essay on the Buddha’s approach to the pursuit of justice.
How to learn judging that is nessesary: The Power of Judgment
And feel, act, judged by the wise: [En/De] In den Augen der Weisen - In the eyes of the Wise, Bhante Thanissaro
To judge best and right mindfulness on your, body, your feelings, your mind and your ideas and mental phenomenas, is what is meant to be mindful, in short.