On this day 154 years ago, Pope Pius IX, speaking ex cathedra, proclaimed the doctrine of the Immaculate Conception, which asserts that Mary the mother of Jesus was, from the first instant of her conception, preserved from all stain of original sin. The idea that Mary had been sinless since conception had been formulated around 1100 AD by Eadmer, an English ecclesiastic, and the feast of the Immaculate Conception was celebrated each year on 8 December, but the idea of the Immaculate Conception was the subject of some controversy and did not become an official doctrine until 1854.
One theological difficulty with the idea of Mary being sinless from conception is that it is difficult to reconcile with the doctrine of universal redemption in Christ. If Mary was sinless, then Jesus did not need to die for her sins, so she was not redeemed by Jesus’s death. Further, it seems to be inconsistent with Romans 3:23 (“All have sinned”) and Romans 5:12 (“Death came to all people, because all sinned”).
The idea of the Immaculate Conception appears to spring at least in part from Augustine’s theory that original sin is transmitted by sexual reproduction, so that a person is stained by sin as soon as he or she is conceived, without any act having been done by the person. This contrasts with a more practical understanding of sin as something which starts after birth when a person deliberately chooses to do the wrong thing.