30. In this context, the theme of integral human development takes on an even broader range of meanings: the correlation between its multiple elements requires a commitment to foster the interaction of the different levels of human knowledge in order to promote the authentic development of peoples. Often it is thought that development, or the socio-economic measures that go with it, merely require to be implemented through joint action. This joint action, however, needs to be given direction, because “all social action involves a doctrine”. In view of the complexity of the issues, it is obvious that the various disciplines have to work together through an orderly interdisciplinary exchange. Charity does not exclude knowledge, but rather requires, promotes, and animates it from within. Knowledge is never purely the work of the intellect. It can certainly be reduced to calculation and experiment, but if it aspires to be wisdom capable of directing man in the light of his first beginnings and his final ends, it must be “seasoned” with the “salt” of charity. Deeds without knowledge are blind, and knowledge without love is sterile. Indeed, “the individual who is animated by true charity labours skilfully to discover the causes of misery, to find the means to combat it, to overcome it resolutely”. Faced with the phenomena that lie before us, charity in truth requires first of all that we know and understand, acknowledging and respecting the specific competence of every level of knowledge. Charity is not an added extra, like an appendix to work already concluded in each of the various disciplines: it engages them in dialogue from the very beginning. The demands of love do not contradict those of reason. Human knowledge is insufficient and the conclusions of science cannot indicate by themselves the path towards integral human development. There is always a need to push further ahead: this is what is required by charity in truth. Going beyond, however, never means prescinding from the conclusions of reason, nor contradicting its results. Intelligence and love are not in separate compartments: love is rich in intelligence and intelligence is full of love.

31. This means that moral evaluation and scientific research must go hand in hand, and that charity must animate them in a harmonious interdisciplinary whole, marked by unity and distinction. The Church's social doctrine, which has “an important interdisciplinary dimension”, can exercise, in this perspective, a function of extraordinary effectiveness. It allows faith, theology, metaphysics and science to come together in a collaborative effort in the service of humanity. It is here above all that the Church's social doctrine displays its dimension of wisdom. Paul VI had seen clearly that among the causes of underdevelopment there is a lack of wisdom and reflection, a lack of thinking capable of formulating a guiding synthesis, for which “a clear vision of all economic, social, cultural and spiritual aspects” is required. The excessive segmentation of knowledge, the rejection of metaphysics by the human sciences, the difficulties encountered by dialogue between science and theology are damaging not only to the development of knowledge, but also to the development of peoples, because these things make it harder to see the integral good of man in its various dimensions. The “broadening [of] our concept of reason and its application”is indispensable if we are to succeed in adequately weighing all the elements involved in the question of development and in the solution of socio-economic problems.

32. The significant new elements in the picture of the development of peoples today in many cases demand new solutions. These need to be found together, respecting the laws proper to each element and in the light of an integral vision of man, reflecting the different aspects of the human person, contemplated through a lens purified by charity. Remarkable convergences and possible solutions will then come to light, without any fundamental component of human life being obscured.

The dignity of the individual and the demands of justice require, particularly today, that economic choices do not cause disparities in wealth to increase in an excessive and morally unacceptable manner, and that we continue to prioritize the goal of access to steady employment for everyone. All things considered, this is also required by “economic logic”. Through the systemic increase of social inequality, both within a single country and between the populations of different countries (i.e. the massive increase in relative poverty), not only does social cohesion suffer, thereby placing democracy at risk, but so too does the economy, through the progressive erosion of “social capital”: the network of relationships of trust, dependability, and respect for rules, all of which are indispensable for any form of civil coexistence.

Economic science tells us that structural insecurity generates anti-productive attitudes wasteful of human resources, inasmuch as workers tend to adapt passively to automatic mechanisms, rather than to release creativity. On this point too, there is a convergence between economic science and moral evaluation. Human costs always include economic costs, and economic dysfunctions always involve human costs.

It should be remembered that the reduction of cultures to the technological dimension, even if it favours short-term profits, in the long term impedes reciprocal enrichment and the dynamics of cooperation. It is important to distinguish between short- and long-term economic or sociological considerations. Lowering the level of protection accorded to the rights of workers, or abandoning mechanisms of wealth redistribution in order to increase the country's international competitiveness, hinder the achievement of lasting development. Moreover, the human consequences of current tendencies towards a short-term economy — sometimes very short-term — need to be carefully evaluated. This requires further and deeper reflection on the meaning of the economy and its goals, as well as a profound and far-sighted revision of the current model of development, so as to correct its dysfunctions and deviations. This is demanded, in any case, by the earth's state of ecological health; above all it is required by the cultural and moral crisis of man, the symptoms of which have been evident for some time all over the world.