 An avid supporter of Descartes, Habert wrote a poem on Cartesian physics entitled "De rerum naturae" and collected scientific instruments.He was a friend of Mersenne, who dedicated his "Harmonie Universelle" to Montmor, and a great friend of Pierre Gassendi, who dedicated to him his "Life of Tycho Brahe".Gassendi also left him an astronomical telescope he had been left by Galileo.