A new essay to analyse the demonstration which Aristotle gave of Barbara ACP (first premise “actual”, second premise “contingent”, conclusion “possible”) is realized with the techniques of mathematicallogic. The critical points (conclusion “possible” from two premises “possible”, problem de dicto - de re, etc) are indicated; based on them it is considered that Aristotle’s proof is not conclusive.

Professor Bunge makes the distinction between the logical concept of existence and the ontological one. I agree with him and in this paper I am formalizing his existence predicate into the powerful language of type theory.I am also proving the logical equivalence of this for mulation with a briefer one, which says that to exist conceptually is the same as to be a conceptual object. Accordingly, from this point on I investigate what conceptual objects are. I reach the conclusion that it is better to study a restricted area each time, where existence could even be assigned in different degrees. For instance, in set theory -like in Animal Farm of Orwell every set exists but so me “exist more” than others. Of course, in relating degrees of existence to degrees of definability I am not following Bunge.

This paper concerns the question whether the rational reconstruction of science provided by the philosophy of science is partly descriptive and partly normative task. To this respect we offer a general characterization of the concept of science and observe then briefly the relations between the history and the philosophy of science. The widely extended view that there cannot be a history of science without an underIying philosophy suggests the problem whether it can exist a rational reconstruction of science independently from any theory about the science. On the answer to this question depends that we could conceive the philosophy of science as a discipline which combines descriptive (or empirical) with normative eIements.

The starting point of the paper is the explicit recognition that the prevalent methodology among economists -namely popperian falsacionism- does not reconstruct as rational the central part of the work of the majority of them. The main thrust of the paper is doublefold. First, a new methodology -abstracted from the analysis of the core of Economic Theory- is proposed which enlarges the scope of rationality in Economics. Second, this new methodology -dubbed the Fix Point Methodology- is posited as a general scientific one. As such it opens new vistas on Truth, specially the conjecture that Reality is a changing entity and the consequent call for professional honesty.

The main aims of this paper are two: first, to show that the current situation of History of Logic is far from being satisfactory, and second, to put forward a programme for its improvement. To this end it is as well, I think, to take into account a new conceptual and historiographical approach to growth of Iogic as a discipline, some basic notions in this regard -e.g., the notion of being a contribution to develop ment of Iogic-, and some others compIementary aspects, commonly neglected by the History of Logic scholars.