Living with others is a "basic" good; and yet is there a precept of Natural Law that commands us to do so? We may speak of a natural inclination to do so, or a natural imperative, but a precept? We may have an inclination to procreate, but this is not a precept for everyone -- the precepts of Natural Law tell us how to choose this reasonably, if we choose it. Some may renounce it for the sake of the Kingdom. But some may be called to renounce human company for the sake of God's company -- to become a hermit. They are not cut off from the supernatural communion that is the Church, but they are removed from participating in human relationships "in this world." (Physically? I think you see what I am getting at.)
It would seem from his treatment of the lawfulness of virginity that St. Thomas would affirm that there is, indeed, a precept to live with others. If someone is not needed for the earthly civitas for its perfection, but set aside by God for something greater, are they dispensed from the precept? I don't see how the duty to live with others can be anything but a duty of the individual. The duty of the multitude, as described by St. Thomas, does not seem to fit in this case: "The other duty has to be fulfilled by the multitude, and the fulfilment of this kind of duty is not binding on each one of the multitude."
Perhaps the response is that one is not really living apart from others--that the supernatural communion the hermit shares with other members of the Church is the fulfillment of the precept. The precept is not be fulfilled at one level, but is at a higher level.
