During the Syncretistic Controversy and Pietistic controversy he represented the extreme orthodox Lutheranism; and opposed especially the younger Calixtus and the theology of the Pietists.
Against Spener, the leader of the Pietists, he charged no less than 263 heresies.
To his scientific interests belonged the development of the so-called Theologia paradisiaca, i.e., that Adam, the patriarchs, and the whole Old Testament agreed with the Augsburg Confession and Formulas of Concord.
To prove this, he published an Antiquissima theologia positiva primi theologi Adami, a Symbolum apostolicum Adami; and Der christlutherischen Kirche Prediger-Beicht und Beichtstuhl von dem grossen Jehova-Elohim im Paradiese gestiftet.
In 1657 Deutschmann married Anna Catharina Calov (Calovius) daughter of the orthodox professor Abraham Calovius.