Current problems at the centre of ethical and legal debate require new thinking regarding the possibility of considering the principle of legal certainty still relevant, in a historical period, the postmodern era, which is dominated by uncertainty and liquidity making difficult to set priorities and benchmarks. In this paper, I will focus on the interpretation that had the greatest consensus among authors who dealt with the concept of legal certainty, which is the ability to foresee Court decisions. My intent is to reconstruct the concept of certainty as predictability, analyzing major legislative changes occurred over the last two centuries
