This paper develops a new interpretation of probability, which sidesteps the usual difficulties intrinsic to the various standard interpretations and, on the other hand, in some sense incorporates much of the intuition behind them. I call it Physicalist Interpretation. The term ``physicalist'' is borrowed from the philosophy of mind. According to the physicalist account of mind, the mental is completely describable in physical terms. In other words, the mental supervenes2 on the physical. Similarly, the main idea of the physicalist interpretation of probability is that there is no such property of an event as its ``probability.'' Rather, I argue that probability is a reducible concept, supervening on physical quantities characterizing the state of affairs corresponding to the event in question. More radically, I claim that probability is a concept which can be completely eliminated from the scientific discourse. The term ``probability'' can be used only collectively: it means different dimensionless -valued physical quantities, more precisely, different dimensionless normalized measures composed by different physical quantities in the different particular situations.
According to this approach, the physical quantity identified with ``probability'' is not the limiting value of relative frequency, and not even necessarily related to the notion of frequency. Although, in some cases, the conditions of the sequential repetitions of a particular situation are such, that the ``probability'' (the corresponding physical quantity) is approximately equal to the relative frequency of the event in question. Neither is ``probability'' a new objective property of a system, expressing its propensity to behave in a certain way, although, the physical quantities characterizing the system are definitely capable to describe such a propensity. In this approach, ``probability'' is not the measure of the degree of belief of an agent in one proposition or another. However, according to the physicalist account of mind, one can imagine a collection of physical quantities characterizing the agent's brain, which compose a dimensionless measure playing the same role in a typical betting scenario as the ``subjective probability.''