Roberto Ardigò, the principal figure in Italian positivism, was born in Casteldidone in Cremona. He became a Catholic priest, but left the priesthood when, at the age of forty-three, he found it no longer compatible with his beliefs, particularly his conviction that human knowledge originates in sensation—a conviction that came to him suddenly, as he recounted it, while staring at the red color of a rose (Opere, Vol. III, p. 368). From 1881 to 1909 he taught history of philosophy at the University of Padua. He spent the last years of his life defending and illustrating his fundamental ideas and debating with the prevailing idealism, which had supplanted positivism as the dominant viewpoint within and without the Italian universities during the last three decades of the nineteenth century. He died in Padua after two attempts at suicide.

The basic interests of Ardig...