What scientific approaches and principles of historical research were developed in the 18-19 centuries?

In the 18-19 centuries, in many states, much attention was paid to historical knowledge. During this period, several factors in the study of history developed. First, the historian must objectively examine historical phenomena. He can analyze, consider, highlight events, but he must investigate them in conjunction with other facts and inseparably from time. In the 18-19th centuries, the concrete historical path of research spread. The scientist must consider all the possible outcomes of an event.