Q361 - What does the Council of Vienne mean by 'the rational soul is the body's form'?

Yes, this council is not the Council of Vienna in Austria do not confuse the two but rather the Council of Vienne in France. It took place between the regions of Lyon and Avignon, not in Vienna, but in Vienne, and it occurred in the 14th century.

When we speak of "form," it is not about the exterior form. The Church teaches that the soul is the form of the body. This means it is a vital principle that gives the body the capacity to live to be a living organism, a living entity. In this context, "form" is a philosophical term. We are often accustomed to using the word "form" to refer to appearance, but here it refers to something interior and metaphysical.

Metaphysical means something that constitutes our being a principle that gives being its essence. In this case, it is the soul that gives the body its being as a living body. Therefore, when the soul separates from the body at the moment of bodily death, the body no longer has life it is dead. When God reunites the soul with the body at the final resurrection, the body will live again, and soul and body will be together.

So, we must understand "form of the body" in this sense: the body is the matter (materia), and the form is the spiritual soul, which gives it life.