The article proves that the prognostic function of historical consciousness is topical. The historical consciousness is the integrity of the three modes of time (past, present and future) with the crucial role of the past. Historical consciousness has a selective character. The article shows that the prognostic function of historical consciousness can be related not only to the future but also to the past. In the article much attention is paid to the history of different views on the prognostic function of historical consciousness. Many philosophers considered the prognostic function of historical consciousness in their research, but they didn»t focus on this question in detail. The author of article is trying to develop the idea of a Soviet historian Yevgeny Viktorovich Tarle about the prognosis for the future. According to Tarle, the prognosis is not the statement of the future «incidents» with the exact date, but is the statement of future «states» of the society. The idea of Tarle about the prognosis is similar to the ideas of Karl Raimund Popper. Popper stresses that the human cannot live without searching consistency with natural laws and trying to prove them. Popper considers the future as the human project.