Dovid Gottlieb (born Dale Victor Gottlieb) is a senior faculty member at Ohr Somayach in Jerusalem. An author and lecturer, Rabbi Gottlieb received his Ph.D. in mathematical logic at Brandeis University and later become Professor of Philosophy at Johns Hopkins University. A student of Jean Van Heijenoort, he received a doctorate in 1970 for his thesis The Use of Formal Systems in Logic and Mathematics. His book Ontological Economy: Substitutional Quantification and Mathematics was published by Oxford in 1980. The phrases "ontological economy" and "the principle of ontological economy" have come to refer to Occam's Razor  ; The Informed Soul was published by Artscroll in 1990, and has recently been reprinted. Living Up to the Truth was published by lulu.com in 1996 and a second edition made in 1997. He is a regular lecturer at kiruv conferences.