Living with the memory of hardship, Vishniac was, “an absolute optimist filled with tragedy. His humanism is not just for Jews, but for every living thing.” He probably believed in God or some similar concept, but he was non-denominational and did not adhere strictly to the principles of any religion. He even clashed with Orthodox Jews in one well-known instance: The religious Jews he met on his trek around Europe would not let themselves be photographed, quoting the Bible and its prohibition of making of graven images. Vishniac’s famous response was, “the Torah existed for thousands of years before the camera had been invented.”
Vishniac was known for having great respect for all living creatures. Whenever possible, he returned a specimen to its precise home before it was captured and one time “[lent] his bathtub to tadpoles for weeks until he could return them to their pond”. In accordance with this philosophy, he photographed almost exclusively living subjects.