The material cause is the method by which the formal cause, the teachings of the Church, will be passed on to the pupil. Catechesis of the Good Shepherd does not use normal teaching methods but relies on means other than a teacher to convey knowledge to the pupil. Building on the method of Maria Montessori, CGS seeks to pass on knowledge through hands-on materials, cooperating with “special knowledge” which the child alone is believed to possess, and thus causing him to have a special relationship with God. This special knowledge allows the child not only to learn through his intrinsic capacities, but the child will also teach the catechists who are mere facilitators within the CGS program.
To understand how the children learn we must examine the child psychology of Maria Montessori, who laid the psychological foundation for CGS.
"With this aim in mind, the catechist embraces Maria Montessori’s vision of the human being and thus the attitude of the adult regarding the child; and prepares an environment called the atrium, which aids the development of the religious life." https://www.cgsusa.org/discover/the-cgs-method-past/the-32-points-of-reflection/
Maria Montessori did not believe that knowledge of God was something which was passed on from the apostles to the rest of the world. Rather, faith and religion are a sentiment that is conjured from within.
“We must remember that religion is a universal sentiment which is inside everybody and has been inside every person since the beginning of the world. It is not something which we must give to the child". Maria Montessori, The child, society and the The Child, Society and the World: Unpublished Speeches and Writings
This same thinking is also repeated by Sophia Caveltti, the founder of CGS.
"She works from the theological assumption that Catechesis offers children the opportunity to relate to God whom "they innately know and perceive." It is not a "catechesis of definition but a catechesis of invitation" ." https://www.biola.edu/talbot/ce20/database/sofia-cavalletti
Thus the child does not need a teacher, but only needs to have this knowledge unleashed, which is what the materials in CGS are proposed to achieve. Since the knowledge would not come through learning things externally but from cultivating the innate knowledge from within, there is no longer a need to cover all the essential content of a catechism course, for the child will come to know and understand God through his own power. This is why Sophia Cavalletti believed she could remove substantial parts of Catholic doctrine which the Church had deemed essential elements of a catechesis program.
"According to Cavalletti, she and Gobbi made many mistakes and had to throw away some of the materials they had created as they searched to find the essential themes and elements that correspond to the needs of the children. Only materials that aroused much interest and deep joy were kept. They were seeking the most essential and the simplest materials that would help the personal work of the children so that the children would be able to grasp the message of the Scripture or the liturgy. Therefore, anything that was not essential was removed from the atrium." https://www.biola.edu/talbot/ce20/database/sofia-cavalletti
Since the catechists are no longer necessary to pass on the Faith and are replaced by inner knowledge, the catechists are reduced to mere facilitators who risk confusing the child if they distract him from listening to his inner sentiment.
"the only Teacher is Christ; both children and adults place themselves in a listening stance before his Word" CGS 32 Points of Reflection
"The catechist is not a teacher, remembering that the only Teacher is Christ himself. The catechist renounces every form of control" CGS 32 Points of Reflection
"The material makes it possible for the catechist to assume his/her proper “post” as “the useless servant.”" CGS 32 Points of Reflection
"The attitude of the adult has to be marked by humility before the capacities of the child, establishing a right rapport with the child, that is to say, respecting the personality of the child, and waiting for the child to reveal himself/herself." CGS 32 Points of Reflection
Another reason the catechist does not teach is that adults do not have the same access to this innate knowledge. Maria Montessori talks about this in her journal article titled "The Child: The Eternal Messiah" in the Theosophical Digest, and we also find this ideology manifest in the writings of Sophia Cavalletti.
"children's deep and mysterious relationship with God, a relationship that she feels is much more serious than that of adults" https://www.biola.edu/talbot/ce20/database/sofia-cavalletti
And below we can see the fruits of this psychology in the CGS program, stating that the child will teach the adults. Though this sounds absurd at first, it makes sense once one understands the psychology of Maria Montessori.
27. The Catechesis of the Good Shepherd is also concerned with helping adults open their eyes to the hidden riches of the child, especially to the child’s spiritual wealth, so that adults will be drawn to learn from the child and to serve him/her. CGS 32 Points of Reflection
If this understanding of the child and his or her relationship with God is false, then we will end up with children who know very little about their religion. This idea that religion is not passed down from the apostles, but is known through an intrinsic sentiment has been condemned by Pope Pius X as an error of the Modernist. This idea that the child has secret knowledge not accessible to others is an error of the Gnostics. Thus it would appear the entire system which CGS has devised, is not, in fact, a system of passing on the Faith, because that is forbidden. Rather CGS is a system for coming to a knowledge of the faith, without passing knowledge from teacher to pupil; this has been condemned as heresy and theological error for virtually the entire history of the Church. Thus, if an internal sentiment is not passing the Faith to the children, then CGS leaves the children with nothing more than a 'joyful experience' from which they have learned very little.