Thinking is a complex process, which humans try to understand since the very beginning of our existence. It includes generation of thoughts, making sense of the existing experience, analysis, drawing conclusions and making conclusions. Modern artificial intelligence systems are trying to replicate this process for different domains starting with texts and now even audio or video. However, generation of new knowledge, correct answers from existing knowledge or solving complex tasks requires step-by-step approach, analysis, sources comparison and even full-on planning or ability to reassess previous decisions. We try to describe the thinking process in this article, derive main properties and compare it to the way modern artificial intelligence models learn information and make decisions. Nowadays the necessity to understand this process more clearly is as relevant as ever, because it will give us an opportunity to classify current or future models as “artificial general intelligence” [1].