Physical probability as a propensity

R. Carnap [3] distinguished probability, from probability2. This paper
is concerned with probability2. Other names for it have been 'empirical
probability,' 'physical probability,' 'chance,' and 'statistical probability.'
We will usually use 'physical probability.' Our standard example will be
the bias of a coin towards, say, heads. It seems to us, as it has to many,
that the property of being biased towards heads is, in some broad sense,
physical and logically independent of the epistemological attitudes of
human beings. It is intimately related to the physical distribution of
matter in the coin and can be (and often is) possessed even though
everyone is ignorant of the fact. The property is, therefore, not to be
analysed in terms of the relation between evidence and hypothesis,
degree of belief or support, and the like, though no doubt it has
connections with such matters. It is, as Carnap held, quite distinct from
probabilit