The time of mechanics is the eternal and unchangeable time of Parmenides, it is Plato’s idea of time, whereas the time of thermodynamics is Heraclitus’ flowing time, Thomas Aquinas’ time measured by various phenomena. I once wrote [2] that people who are not used to a physicist’s way of thinking are (at best) confused by the idea of a symmetrical time of mechanics. Physicists on the other hand often believe that the time of thermodynamics (irreversibility) does not really exist, and is merely an illusion. It seems therefore that both of these aspects of time, the time of mechanics and the time of thermodynamics, should be treated as complementary, in anticipation of a future “theory of everything” which will somehow reconcile them.

The paper consists of two parts, outlined in the title.I. In the historical science time appears as an element of the historian’s workshop. The historian collects source information, evaluates them and assigns respective dates. Only on the ground of thus “processed” sources may he reproduce the past: events and longer development processes, setting them in time. This dated time is understood colloquially as something objective, which runs one way and may be measured.II. A historian who studies the past reality depends on the extent to which those sources are preserved. As a result of their interpretation, with the use of increasingly excellent research methods, he reproduces that reality. He must carry out an ongoing selection of historical facts found. This exposes him to temptations of such selection of those facts so as to adjust the historical knowledge to serve well the national interests, his own political opinions, etc. In this way the historian exerts influence on social awareness, which may consists of various myths and stereotypes, which sometimes lead to negative social behaviors: aggression, chauvinism, etc. Therefore, for researcher honesty’s sake and in the sense of moral responsibility, he must be careful to be as impartial as possible in his work.

In his classic essay Man and Time, Roman Ingarden outlines two contradictory experiences of time. The paper presents and investigates them.

Despite changeability of the world, the human mind also ponders on those quantities that remain constant over time. This was the case in ancient times, in the middle ages, and the same applies in modern physics. This paper discusses i.a. Zenon paradoxes, the principle of inertia, and the Emma Noether theorem, ending with the modern, so-called Zeno’s quantum effect. The foot-notes concern the ancient “Achilles” paradox, spot speed, as well as some of the facts taken out of the life-history of Emma Noether, as well as the example of applying her theorem.

Certain aspects of time physics were considered within the framework of quantum cosmology of the closed universe. Based on the general relativity we know that total energy of the closed universe is precisely equal to zero. This fact allows interpreting the creation of the closed universe as a spontaneous, causeless occurrence of respective quantum fluctuation, without any energy input. However, in such a universe the unitary evolution is “frozen”—no changes may occur, i.e. the universal cosmic time, which numbers the changes in the state of the universe, cannot exist. This conclusion is obviously contrary to the experiment. For this reason the changes observed in the closed universe may be generated solely by non-unitary, irreversible and jumpwise evolution, associated with quantum measurement, which cannot be caused by any element of reality liable to linear laws of quantum theory. Therefore, quantum cosmology does not generate a closed thinking system. In consequence, this leads to an ontology called objective idealism.

Our article is an overview of a selection of findings in physics relating to the issue of time—we do not present in it any “time theory” of our own. After making some general remarks on the issue of time, we present historical outline and a brief description of the current state of time interval measurements. Subsequently, we go on to discuss certain (relating to the concept of time) consequences of both theories of relativity: special and general. Here, time is a geometrical component of space-time continuum. Following section is dedicated to time in the so-called Hamiltonian formulations of the theory of particles, where it appears as a parameter of evolution. The last section contains remarks referring to certain attempts of going beyond the recognized physical theories relating to the question of time.

I shall outline the topic from a historical perspective, placing the main emphasis on the hundred years’ period spanning 1870–1970.

Traditional hardcopy publishing brought about a division of labor between producers and disseminators of information. Online publishing makes it feasible for authors to disseminate their work much more widely without any investment in equipment beyond the ubiquitous laptop, without labor costs and without any special technical expertise. As a consequence, the division of labor is no longer important and is, in a range of cases, inefficient. For some scholarly works and teaching materials in particular, traditional hardcopy publishing rather than rather than facilitating the dissemination of creative works not only restricts access to these materials but also undermines their production. Arguably, hardcopy journals and textbook anthologies, are inefficient and only persist because of institutional inertia and what has become the vicious circle of academic publishing.