On the basis of a new system of logic Łukasiewicz now tried to construct such a definition of the concept of possibility, which would allow him to justify all intuitive propositions handed down for modal statements without contradiction.
> I considered the notion of "pure" possibility, and soon found a definition which satisfied me.
Later, however, he became convinced that the more general concept of possibility *in general* (Möglichkeit *überhaupt*) was preferable to the narrower concept of *pure* possibility, and we therefore discuss below a definition of this latter concept which fully meets the requirements set out earlier in propositions I - III.