Plato's doctrine of recollection, however, addresses such criticism by saying that souls are "born" with the concepts of the forms, and just have to be "reminded" of those concepts from back before birth, when the souls were in close contact with the forms in the Platonic heaven. Plato is thus known as one of the first rationalists, believing as he did that humans are born with a fund of "a priori" knowledge, to which they have access through a process of reason or intellection — a process that critics find to be rather mysterious.