The paper considers the problem of uncertainty and outlines some means to overcome it. It demonstrates that both nature and man possess the dialectical property of uncertainty. The authors set out main reasons why in the XXI century uncertainty manifests itself in all spheres of society, including education. They also highlight the most vulnerable position of high school students who as yet lack life experience in a situation of uncertainty and pay attention to the complexity of the tasks facing their teachers. The main emphasis is placed on the main ideas of the "Pedagogy of Cooperation" developed by V.F. Shatalov, Sh.A. Amonashvili and S.N. Lysenkova. These ideas are aimed to help students overcome a situation of uncertainty. The paper emphasises that the pedagogy of cooperation allows teaching all children equally effectively, regardless of their natural abilities, since it is based on the laws of psychology and didactics of I.P. Pavlov, J. Miller, G. Ebbinghaus et al. The researchers point out that the quality of school-book texts becomes especially important in the process of transition to the use of electronic forms of a printed textbook. They explain why sorting students in classes by grades, dividing them into "physicists" and "lyricists" can be harmful, especially in modern conditions. The authors conclude that teachers' professionalism, various competencies, experience, and constant self-education are a way and a guarantee of overcoming uncertainty in the conditions of modernisation of education and the introduction of digital technologies.