Pasha was born in Oppeln, Silesia, into a middle-class German Jewish family, which moved to Neisse when he was two years of age. After the death of his father in 1845, his mother married a Christian; she and her offspring were baptized Lutherans. He studied at the universities at Breslau, Königsberg, and Berlin, qualifying as a physician in 1864. However, he was disqualified from practice, and left Germany for Istanbul, with the intention of entering Ottoman service. He added greatly to the anthropological knowledge of central Africa and published valuable geographical papers.