"We need to develop a new synthesis capable of overcoming the false arguments of recent centuries" (Laudato si' 121). Today, we are increasingly aware of the urgent need for a new way of thinking that bridges divides—between humans and nature, economy and ecology, short-term gain and long-term sustainability. Could sustainable development provide this new synthesis? At first glance, it might appear so. But is it the solution?

First and foremost, this depends on what we mean by "development," a term that has become worn out and often used as a mere synonym for "growth," narrowly focused on economic expansion. Furthermore, modern science offers us a different, more complex view of reality in which everything is interconnected, revealing that we are part of a web of relationships that extend beyond individual entities. This interconnectedness calls for a paradigm shift which embraces, rather than simplifies, complexity—one that sees sustainability not as a linear goal but as a dynamic process supported by the quality of relationships among people, society, and the environment.

Relational sustainability arises from a worldview rooted in the fundamental connectedness of all things. (1) In this perspective, neither human existence nor nature alone takes precedence; instead, their relationship is primary. (2) This relationship-oriented view of sustainability moves beyond isolated efforts and recognises humanity as an integral part of the cosmos. Here, sustainability becomes not a fixed state but an ongoing, co-creative process, emerging from the harmonious interplay between people and nature, guided by the pursuit of the common good. In this view, "sustainability" is the central goal, while "relational" defines the approach, emphasizing that the essence of sustainability lies in nurturing strong, quality connections that foster the common good. (3) Building constructive relationships—between humanity and the cosmos, between individuals, and among human groups (families, communities, institutions, nations)—lies at the heart of relational sustainability. When these relationships prioritise the common good, (4) they generate "relational goods": qualities of connection with intrinsic value. (5) Relational goods are thus sustained, shared connections that support individual and collective flourishing.

Relational sustainability is the practical counterpart, or "concrete side," of integral ecology, which embraces the interdependence of human, social, and environmental dimensions. Imagine a coin with two faces: on one side is integral ecology, the broad vision of interconnected life, and on the other, relational sustainability, the means of realizing this vision. The value of this "coin" is generated by human creativity and industriousness, where the mission of relational sustainability takes shape through diverse fields—such as architecture, art, communication, law, ecology, economics, medicine, pedagogy, political science, psychology, sociology, and sports. The value of relational sustainability is realised through practical, intentional efforts across diverse fields, each contributing to a framework of interconnected well-being.

The objectives of relational sustainability are thus centred on cultivating a model of development that prioritises the quality and interconnectedness of relationships among individuals, communities, and the natural world. Specifically, it aims to:

1. Promote the Common Good: Relational sustainability shifts the focus away from individualistic or purely economic goals to build a shared good that benefits both humanity and nature. This objective emphasises fostering environments where people and ecosystems can flourish in harmony, generating "relational goods" that enrich communities. This approach shifts the growth focus to the relationships themselves—those connections that make sustainability possible across environmental, (6) social,  (7) and economic (8) dimensions.

2. Encourage Interdisciplinary and Transdisciplinary Collaboration: (9) Relational sustainability recognises that sustainability challenges are complex and interconnected, requiring the insights and approaches of multiple disciplines. Relational sustainability promotes dialogue and collaboration across fields—economics, ecology, sociology, philosophy, and others—to address social, environmental, and economic issues in an integrated way.

3. Support Co-creative and Reciprocal Relationships: Relational sustainability encourages policies and practices that foster collaborative, mutually beneficial relationships between individuals, communities, and ecosystems. This objective underscores the dynamic nature of relational sustainability, where humanity and nature support each other in a balanced, evolving relationship.

4. Establish Complementary Indicators of Well-being: While GDP remains an important economic measure, it does not capture the full picture of societal and ecological health. Relational sustainability calls for additional indicators developed through interdisciplinary and transdisciplinary collaboration, reflecting the quality of relationships, social cohesion, and environmental integrity. These complementary metrics would assess "authentic well-being," measuring aspects such as life quality, ecological balance, and the long-term sustainability of human and natural communities.

These objectives collectively aim to reshape sustainability as a relational and interconnected endeavour, where success is measured not only by outcomes but by the vitality and resilience of the connections that sustain life and foster the common good.

This Manifesto commits to supporting networks, organizations, and community groups dedicated to advancing relational sustainability by harmonizing complementary approaches like circular economy, happy degrowth, and cooperative practices. Rather than replacing existing frameworks, relational sustainability aims to enrich them, fostering a model that serves both humanity and the environment in enduring ways.

To realise this vision, we call for openness and a transdisciplinary approach—embracing diverse perspectives and fostering collaboration across fields. Only by acknowledging the complexity of our interconnected world can we develop strategies that honour and sustain the intricate relationships defining life.

Finally, this Manifesto invites all individuals, communities, and institutions to engage in relational sustainability. By prioritizing and nurturing these vital connections, we can collectively work toward a common good that transcends individual interests, ensuring a resilient and thriving future for all.

(1) In its relational aspect, this proposal is inspired by the thought of Chiara Lubich (1920-2008), a multifaceted personality of the Italian 20th century who founded the Focolare Movement and made universal brotherhood one of its key messages. In one of her writings, she says: “The progress of man is closely linked to the progress of the environment in which he lives and by which he is conditioned. […] If […] the end of man is not economic interest, selfishness, but love for others and nature, with his contribution the earth will be transfigured until it becomes a paradise on earth”. (quoted in L. Fiorani, Il contributo di EcoOne alla riflessione ecologica, in “Nuova Umanità” XXXIV, 199, 2012, pp. 49-51). 

(2) In this regard, it is interesting to cite Miguel Panao's effort to overcome anthropocentric and physiocentric views by emphasising not the actors in the relationship but the relationship itself with the concept of Communiocentrism (M. Oliveira Panão, What Is the Relation with Nature of a Self-giving Person? Proceedings of the International Meeting ‘Relationality: Between Environmental Awareness and Societal Challenges’, L. Fiorani, Z. Román, V. Falcioni, F. Geremia (editors), ENEA, Rome, 2017, pp. 35-48). In this context, there is a need for a language change, still unbalanced in the sense that the protagonist is the human person.

(3) Relational sustainability is akin to what Laudato Si' calls "liberating sobriety" and resonates with the concept of buen vivir (good life) found in the Bolivian and Ecuadorian constitutions. This vision emphasises "a full and dignified life, a harmonious existence that includes cognitive, social, environmental, economic, political and cultural dimensions, all of which are interrelated and interdependent".

(4) According to Maritain, the common goods are "the good human life of the multitude, of a multitude of people; it is their community in living well; it is, therefore, common to the whole and the parts" (J. Maritain, La personne et le bien commune, Desclée de Brouwer, Bruges, Belgium, 1946). 

(5) According to Gui, "Relational goods are interpersonal relationships of quality that have a value in which to invest" (B. Gui, On "Relational Goods": Strategic Implications of Investment in Relationships, International Journal of Social Economics, vol. 23-10/11, 1996, pp. 260-278).

(6) Environmental dimension: humanity must not exceed the limits set by the earth's capacity to renew resources and eliminate pollutants (why not include this principle in the constitutions of countries, following the example of the Earth Charter approved by UNESCO?)

(7) Social dimension: we must build increasingly just societies; it is unacceptable, for example, that 10% of the world's population owns more than 50% of its wealth and that the Mediterranean continues to be the grave of desperate people, including children, fleeing war, persecution and poverty.

(8) Economic dimension: we must pursue the authentic well-being of all the peoples of the planet, ensuring that every person has the goods that allow them to satisfy a good quality of life (primarily, but not exclusively, water, food, clothing...) and not the unrestrained consumerism that culminates in the culture of waste. 

(9) See the definitions of Jean Piaget and Basarab Nicolescu.