Complex sentence: Beecher believed that rules requiring informed consent were not by themselves sufficient, as truly informed consent was an unattainable ideal but worked both in defining the rules and conditions for informed consent and in establishing institutional review boards as an additional layer of oversight regarding research protocols.
Split into simpler sentences: Beecher believed that rules requiring informed consent were not by themselves sufficient, as truly informed consent was an unattainable ideal. He worked both in defining the rules and conditions for informed consent and in establishing institutional review boards as an additional layer of oversight regarding research protocols.