In general usage, discernment means good judgement, seeing things for what they are.
The word is often used in the context of seeing the difference between right and wrong or true and false. In religious discourse, discernment specifically means distinguishing between different spiritual influences.
We could say that building discernment is the core of esoteric work. If being is like the light which illumines man's inner world and allows it to be seen and to act as a coherent whole, discernment is the act of seeing by this light.
Discernment is a sense for the true nature of things. Discernment is a skill or ability rather than the state of possessing information. Discernment may apply to all manifestations of the universe, as they all ultimately derive from archetypal sources. Discernment cannot be codified into a set of universally applicable rules but it can be learned through practice. While some general principles exist, all situations are unique. Discernment is the capacity to see what is applicable to what. Discernment, as knowledge itself, is infinitely varied and all-encompassing. Discernment does not occur in a vacuum, it is always in relation to a situation, a phenomenon or message.
Discernment has to do with awareness of context. In 4th Way discourse, we could say that discernment is the capacity to correctly see the three forces, active, passive and neutralizing as they apply to a situation.
The concept of discernment has a supersensible element, as in a spontaneous apprehension of what is true and what false. This is an attribute that is strengthened along the path of esoteric development. After the fact, it is often possible to say which signs or criteria of judgement led to which conclusion, yet discernment cannot be reduced to applying checklists to phenomena or situations.
Discernment is necessary for making sense of any esoteric writings. The first difficulty is external: The writings have been deliberately twisted along the line of transmission or the cultural context is not properly understood, giving rise to faulty interpretation of any allegories, not to mention errors of translation between languages. The second difficulty persists even if the first were overcome: Words have multiple meanings, for example ‘I' in one sentence may mean something completely other than in another. The problem is compounded if comparing different sources.
Discernment applies to man's inner life as well as to outer manifestations. For example, Gurdjieff says that self-love isolates man from reality and prevents esoteric development. Yet a different part of the self must be of great worth and loved a great deal in order to justify the efforts made on its behalf in the Work. Suffering of one sort is wasted energy, merely feeding the moon, yet other suffering is absolutely necessary for obtaining anything. Distinguishing between the parts of self concerned and the types of effort and suffering is an example of discernment applied to inner life. Each of these has its proper 'taste,' which must be linked to the terms used in the teaching before the teaching comes to life.
Examples of discernment applied to the outer world include seeing through the lies and misrepresentations of politics without the veil of wishful thinking. Even further, discernment applies to what is or is not known. Discernment is the opposite of belief or obsession, it is an ever-vigilant state, knowing the limits of its own knowledge. Another application is seeing the patterns of history through the layers of disinformation accumulated at each retelling. Another application is extracting information of value from esoteric or channeled sources. Even if an invariably truthful source of information existed, the information would be of little value without the capacity of discernment which would confirm its truth, thus making the information the receiver's own.
We could say that the principal aim of the FotCM is practicing and teaching discernment as applies to both inner and outer contents. Only if the world is seen for what it is is it possible to choose one's way and act in favor of this choice. In this sense, all begins with discernment of both one's circumstance as well as of one's inner nature. All that follows calls for increasingly refined discernment between influences, situations and choices.