If so, we know that the change is a genuine development, not a corruption.
Newman warns that the presence of any alteration in the external expression of an idea shouldn’t lead us to conclude that it’s a corruption, instead of a development, of the essential idea.
The third note of genuine development is In introducing this criterion, Newman notes that in the physical world living things are characterized by growth, not stagnancy, and that this growth comes about by making use of external things.
For example, as human beings we grow by taking into our bodies external realities such as food, water and air.
The second note of genuine development is continuity of principles.
Newman insists that for a development to be faithful, it must preserve the principle with which it started.He considered this first criterion the most important of the seven.What he means by type is the external expression of an idea.While doctrine may grow and develop, principles are permanent.Newman identifies the Incarnation as the fundamental truth of the Gospel.In fact, in the process of assimilation it’s the external realities themselves that are transformed (once they are assimilated), not the doctrine.In Newman’s view, the more powerful, independent and vigorous the idea, the greater its power to assimilate external ideas and concepts without losing its identity.Pelagians denied the reality of original sin and, as a consequence, denied that our salvation required any grace beyond what is already given us in human nature.As a result, the Church recognized the movement as a heretical corruption rather than a development of the Christian faith, and so condemned its teachings.Their growth in richness and complexity represents the change from an embryonic form into maturity.But how are we to demonstrate whether or not a particular doctrine (or body of doctrines) is a genuine development and not a corruption of the Christian faith?