The limbs of infants are tiny, while those of young men are large, but they are the same limbs. The man has no more parts to his body than the little child; and if there are parts that appear with age and greater maturity they are already present earlier in embryo. As a result, it can be said that nothing new is produced in old men that was not already present in an undeveloped form when they were boys.
Is there to be no development of doctrine in Christ’s Church? Certainly there should be great development. Who could be so grudging towards his fellow men and so hostile to God as to try to prevent it? But care should be taken to ensure that it really is development of the faith and not alteration. Development implies that each point of doctrine is expanded within itself, while alteration suggests that a thing has been changed from what it was into something different.
It is desirable then that development should take place, and that there should be a great and vigorous growth in the understanding, knowledge and wisdom of every individual as well as of all the people, on the part of each member as well as of the whole Church, gradually over the generations and ages. But it must be growth within the limits of its own nature, that is to say within the framework of the same dogma and of the same meaning.
Let religion, which is of the spirit, imitate the processes of the body. For, although bodies develop over the years and their individual parts evolve, they do not change into something different. It is true that there is a great gap between the prime of youth and the maturity of later years, but the people who reach these later years are the same people who once were adolescents. So, although the size and outward appearance of any individual may change, it is still the same person, and the nature remains the same.
There is no doubt, then, that this is the correct and legitimate rule for development and the best and most striking order of growth, if the passage of years sees those parts evolve in the adult, which the Creator in his wisdom had prepared in him beforehand when he was a child.
But if the human form is changed into some shape that is not of its own kind, or at least if something is added or taken away from the full compliment of its members, than the whole body must perish or become a monster or at least be weakened in some way. It is fitting, then, that Christian doctrine too should follow these laws of development, so that with the passage of years it may be strengthened, with time it may make progress and with age it may achieve greater profundity.
Long ago our ancestors sowed the seeds of the faith in the field of the Church. It would be quite incongruous and wrong if their descendants were to reap the weeds of error in place of the harvest of truth.
St Vincent of Lerins, Commonitorium, 1, 23; The Divine Office III.