The Church has never lacked the Scriptures to guide her deliberations, nor her belief in the dignity of the human being, created in the image of God and redeemed by Christ. To this Faith, which is always first in her consideration, she has added theology, which with the assistance of philosophy, seeks to deepen the understanding of the Faith.
As noted above, the early Church took a strongly evangelical approach, unmoderated by other considerations, which only developed over time, and which accompanied the insertion of Christians into civil society. In recent centuries we have seen the almost complete undoing of what came to be considered the Christian West. In a famous lecture in 1958, the future Pope Benedict XVI described this reversal, stating that the Church was no longer,
… composed of pagans who have become Christians, but a Church of pagans, who still call themselves Christians, but actually have become pagans.
Emblematic of this was the 20th Century, the most violent in history, both as a result of warfare, but also in terms of violence motivated by hatred based on political, ethnic, and religious differences. According to the Commission for the New Martyrs of the Great Jubilee, established by Pope St. John Paul II, the number of Christian martyrs alone in the 20th century was double that of all other centuries combined––as high as 26 million.
This violence, largely the fruit of materialist philosophies such as Communism and Nazism, prompted a general philosophical reassessment of the relationship between human beings considered as a thing (a nature), and considered as a person. The resulting philosophical perspective known as Personalism developed between the two World Wars as a reaction to the increasing devaluation of the human person, which continued after WW II down to our day. When the Church and others refer to the increasing sense of the dignity of the person it is referring to this violent history and the reaction to it, which is found among people of many faiths and no faith.
The fruits of personalism, unfortunately, have been decidedly mixed. Outside the Church, and even among some Catholics, it took an existentialist turn, exalting the personal autonomy of the individual (e.g. the prochoice movement), and recently even reducing human sexual nature to a personal choice (e.g. gender ideology). At the other extreme, materialist philosophies persist, in worldviews such as socialism, fascism and some forms of capitalism, aided by the general reduction of human life to a natural life, devoid of moral absolutes--what Pope Benedict XVI called the Dictatorship of Relativism.
The Catholic approach has been different, for being the mean between extremes. The Church recognizes that whatever contribution personalism can make to understanding the human person, it cannot be rightly effected without respecting the authentic knowledge of human nature, which reason can discover and the Church possesses in her perennial philosophy, and it absolutely cannot proceed apart from Divine Revelation and the teaching of the Magisterium. The truths of the latter are guaranteed by something far more certain than human reason, as operative in theology and philosophy, or in the natural and human sciences, they are guaranteed by God revealing and by Christ’s promises to the Church.
On this basis, therefore, the Magisterium has embraced personalism, righty understood and applied, as a handmaid to theology for understanding the human person philosophically, as it did Aristotelianism in the 12th century, as a handmaid to theology for understanding being and nature. The influence of personalism can be seen, therefore, in the documents of the Second Vatican Council and the Papal Magisterium, and especially those of Pope St. John Paul II, whose priestly work as a university and seminary professor in Krakow prior to becoming a bishop, was in this area of ethics.
Finally, many have NOT been persuaded by the arguments that either Pope St. John Paul II made, or Pope Francis makes today in their teaching on capital punishment. In a document promulgated by then Cardinal Ratzinger on The Ecclesial Vocation of the Theologian, the Prefect of the Congregation for the Doctrine of the Faith makes several points, which clarify what ought to be our attitude in such a case. While written for theologians, it is applicable to all believers.