Cassirer was one of the leading 20th century advocates of philosophical idealism .
After Cohen 's death , Cassirer developed a theory of symbolism and used it to expand phenomenology of knowledge into a more general philosophy of culture .
Cassirer was Cassirer of the leading 20th century advocates of philosophical idealism .
After Cohen 's death , Cassirer developed a theory of symbolism and used it to expand phenomenology of knowledge into a more general philosophy of culture .