The modern theories of information opened to way to extraordinary new tools for communication and knowledge construction. When identified instead with the world (DNA is a complete information carrier and a program for ontogenesis, atomic particles and planets exchange information …), a new form of scientism affects knowledge and trust in science. Vague and implicit assumptions, with no precise references to the sciences of information, force strong consequences, in biology in particular. Similarly, the powerful optimization methods that make intelligible the dynamics of inert matter are expected or used to direct also human activities and replace human government by automatic governance. We are then meant to follow the formal, mechanical rule or the unique optimal path, instead of inventing new forms of sense in human interactions. Yet another fantastic tool, the newly available Big Data, is being considered to substitute scientific invention by correlations among numbers: fortunately, mathematics a priori shows that a deluge of spurious correlations may be found in any very large set of numbers. An ethics of knowledge may then be proposed in order to reconstruct the trust in science, as critical thinking at the heart of democracy. 1-The sciences of Information The concept of information has been dealt with by at least two rigorous and important scientific theories: elaboration of information, after Alan Turing, and communication or transmission of information, after Claude Shannon. These two theories are based on fundamental properties of mathematical invariance, which is to say these authors singled out some key mathematical 1 Extended and revised synthesis of an interview by P. Bartolini in Italian (ROARS, september 2016), translated into English by M.R. Doyle and S. Savic. In A. Fabris (ed.), Trust, Studies in Applied Philosophy, Epistemology and Rational Ethics 54, Springer 2020. *** Free access: https://www.di.ens.fr/users/longo/files/Trust-InfoScientism-exInterv.pdf