Thanks for your questions! I am afraid I am not very positive about what often goes by the name of "common sense"! I think that more often than not, I would call it common nonsense! I remember when I was inviting people to my consecration, I met one of the residents in the complex (a Catholic) in the hallway and told her what would be happening at the parish church. She looked a little puzzled so I thought I would start at the beginning and asked her if she knew what a hermit was. She responded, "Sure, it's someone who wants to escape. . ." and at that point her voice trailed off. Another time I was introduced to someone as a hermit. Her immediate response was, "Why aren't you home in your cave?" and then she realized what she had said when the usual social filters fell away, and she flushed with embarrassment.
In more serious examples, I have often written over the years that eremitical life, contrary to popular opinion, not individualistic or isolationist, and that solitude, precisely because it is a matter of being alone with God through Christ in the power of the Spirit, is very much a communal reality that includes all grounded in God. There is nothing "common sense" about that. Most people I have spoken to are surprised when they hear this, or when they hear that the life is not a selfish one given over to self-centered pursuits and concerns, or when they learn that one is withdrawing from things in order to be more closely and truly related to them. You can hear the paradoxical nature of so much of this, and that is definitely not what most folks call "common sense"!I agree that generally speaking if a life seems to be unhealthy for someone, that means this is not their vocation. However, it is possible for someone to try to live something they have understood in an ill-defined way or are living in unhealthy ways which, if changed might make the life far more lifegiving and healthful for the person. In such an instance, the person might discover a true vocation. Consider what happens if hermit wannabes lived penance in the ways some have conceived it in past centuries with tons of fasting and corporal mortification. Let's say the person has diabetes or some sort of GI problem; what would happen to their health under such a penitential regimen? Some of us recognize that a regular medication regimen and a careful eating plan could well constitute a piece of sound penitential practice, but you can imagine what some who are truly unschooled or literalistic in their approach to this might replace the healthy praxis with!
Moreover, some approaches to penance treat it as synonymous with punishment and link it to shame and guilt as well. This is a serious misunderstanding or constellation of misunderstandings and with such an approach to penances (or ascesis), one's understanding of God can be completed skewed and with that, any possibility of getting eremitical life right or having it be lifegiving. But penance is not about punishment, and it is not to be connected necessarily with guilt or shame, much less foster these!! When an element of the spiritual life, whether eremitic or non-eremitical, is built into the life, that life will become unhealthy, whether the person really has this vocation or not. This is because such skewed notions of penance or other central elements of c 603, for instance, do distort our senses of our self and the God who calls us to wholeness -- if we can even recognize what wholeness is!Each of the central elements of c 603 and so, of solitary eremitical life as the Church understands it, can be distorted because of ignorance or skewed theologies. When this occurs, they will lead to further skewing and other elements will become distorted as will the witness value of the life. This means that it will not serve others in the way it is meant to serve, namely, as a model of a life centered on Christ in relation to a God whose love is unconditional and whose mercy is gratuitous. Whether we are looking at an overly literalistic and individualistic notion of solitude, a distorted notion of prayer rooted in tendencies to measure things in terms of human achievement, a notion of hiddenness that is mainly defined by externals, we may end up with a distorted understanding of contemporary eremitical life, and that is apt to be singularly unhealthy.
There is an interplay between local Church and hermit or hermit candidate in the way the central elements of c 603 are to be defined. The hermit or hermit candidate lives the elements as she feels called to do and the local Church (through the formation team and mentor) evaluates this in relation to other hermits, the eremitical tradition, the needs and insights of the Local Church, etc. There are essential senses that all hermits tend to agree on and variations of these individuals may feel called to live instead. The local Church evaluates all of this and discerns whether the entire life may honestly be called eremitical and healthily eremitical. The idea is to get a unified and healthy vision and praxis of how this person will live this vocation if it is agreed this is what she is called to in the Name of the Church. The normative elements of c 603 are important and one must live them with integrity; at the same time that does not require slavish fidelity to a dictionary definition of a particular word or value, Instead genuine faithfulness may require relative flexibility within a field of meaning.