In the first chapter of his book, The Intellectual Life, Sertillanges peers into the facets of the intellectual vocation. Three conclusions emerge: the intellectual has a sacred call, he does not stand alone, and belongs to his own time.
One cannot pursue the intellectual life who has not at least the smallest spark of desire for the discovery of Truth for its own beauty as opposed to some self-directed end. In other words, the intellectual doesn't search for truth so that he can do something with it for himself, but because the truth is worth knowing (he must do something with the truth, but that is the secondary and unselfish in nature, as will be seen below). The same Spirit that invested Bezalel and called Oholiab to design the tabernacle and carry out its construction invests men with the intellectual vocation. No Spirit, no vocation.
Sertillanges emphasizes the value of solitude for the intellectual, but he does not equate solitude with isolation. Isolation is poisonous to the intellectual life. The Spirit that fills the intellectual also fills the body of Christ, and so the intellectual who is not participating in the life of that Body is cut off from the Spirit and from a necessary constituent of the intellectual vocation. He draws from the Body as well as contributing to it.
Not only the Church, but also the City and his Time are communities in which the intellectual lives and serves. Although the intellectual touches all points of time through his study, he is uniquely set within the time and place where he lives, and must be attentive to the characteristics, needs, and opportunities his time and place afford. The intellectual looks back to draw upon history so that he may serve in the now and open an avenue for the communities of the future. There is a kind of universal horizon of koinonia among past, present, and future that the intellectual stewards by his labor.