Jiri Raclavsky

It is sometimes objected that Tichý’s logic is not a logic because it underestimates deduction, providing only logical analyses of expressions. I argue that this opinion is wrong. First of all, to detect valid arguments, which are formulated in a language, there needs to be logical analysis to ascertain which semantical entities are involved. Entailment is defined as an extralinguistic affair relating those constructions. The validity of an argument, composed of propositional constructions, stems from the properties of the constructions. Such properties are displayed by the derivation rules of Tichý’s system of deduction

The paper describes the solution to semantic paradoxes pioneered by Pavel Tichý and further developed by the present author. Its main feature is an examination (and then refutation) of the hidden premise of paradoxes that the paradox-producing expression really means what it seems to mean. Semantic concepts are explicated as relative to language, thus also language is explicated. The so-called ‘explicit approach’ easily treats paradoxes in which language is explicitly referred to. The residual paradoxes are solved by the ‘implicit approach’ which employs ideas made explicit by the former one.

Although finding does not seem to be logically and philosophically so much interesting as seeking, the present study gives exhaustive survey of logical analyses corresponding to kinds of finding. There are four basic groups of findings : I) finding by accidence, II) finding after seeking which is typically relation between an agent and an intension, III) finding after finding an instance of intension to which was an agent related by seeking, IV) finding pejorativelly reported. Only type II) can be considered as a notional attitude because it is a relation to an intension ; moreover, this relation is unique in the sense that agent is related just and only to one exact intension.

In his conception of worlds 1-3 Popper did not make clear how the world 3 can influence on world 2 or 1 . On example of music we can see that any human invention of “new” tone combination cannot affect already given tone combinatorics which is in world 3 . Similarily “new” scientific theory cannot make any change in world 3 where all theories are – according to Popper – settled. Opposite direction of influence seems neither possible: human mind can only feel that it is somehow touched by abstract object during its creative activity; to all appearance abstract objects cannot causaly affect on – presumably material – medium of human thinking