 As regards the time when the individual soul is created, philosophical speculation varies.The traditional philosophy of the Roman Catholic Church holds that the rational soul is created at the moment when it is infused into the new organism.Thomas Aquinas, following Aristotle's embryology, taught that rational soul is created when the antecedent principles of life have rendered the foetus an appropriate organism for rational life, though some time is required after birth before the sensory organs are sufficiently developed to assist in the functions of intelligence.