I remember how an elderly philosopher told about an experiment with three waters (warm, medium and ice), on the basis of which he argued that the concepts of "warm" and "cold" are subjective, like all human senses, so they cannot be relied on. I then argued with him for a long time about this, trying to explain that these concepts are just objective, it is necessary to perceive them not as a quantitative assessment (temperature), but as a qualitative direction of heat transmission. However, he did not want to accept my point of view, and in the end everyone remained with their own opinion, with the firm conviction that the opponent is a fool.