Verisimilitude

Verisimilitude, even verisimilitude, in the critical rationalism is a measure by which you can compare which of two false theories is a better approximation to the truth and what is more precise of two true theories. The idea of such a measure is necessarily purely fictitious and only model applicable since the actual truth should be known in order to apply it to theories in practice. An adequate definition of verisimilitude would allow it anyway, at least to speak meaningfully about the possibility of progress in science.

Popper, the founder of critical rationalism, the notion of truth was initially skeptical: " In the we have outlined structure of the logic of knowledge we can refer to the use of the terms 'true' and 'false' without. " Only after he met Alfred Tarski and with had explained the semantic concept of truth, he accepted the importance of the concept of science.

Definition

Popper's first attempt at a definition was based on the postulate that the verisimilitude of a theory is larger than that of a theory, if their truth and falsity contents can be compared and if one of the following properties is satisfied:

Truth and falsity content are the set of true or false sentences that can be derived from the theory.

Popper then defines the verisimilitude of a theory as

Being and a measure of the truth or falsity-content of the theory.

Criticism

Independently found Pavel Tichý and David Miller out that Popper's first definition is inadequate because you can conclude from this that all false theories have the same truth nearby. David Miller suggests as an alternative, not to define the truth and falsity content of a theory about what one can derive from it, but on classes of models. Miller defines the truth of a theory than the class of models that do not describe the real world and in the theory is invalid, and the falsity content than the empty set, if the theory is true, and the crowd with the model of the real world as element, if the theory is wrong. Then, imagine that as if and only truth closer than a theory, if the truth of a proper subset of the veracity of and Falschheintsgehalt of a proper subset of the falsity content of is, so can the validity of the following characteristics show a theory:

At trial, the truth proximity to determine numerically, was not only criticized that his results were unusable. After Herbert Keuth it contains any serious conceptual error. He was contradictory and not defining a measure. There was no adequate basis on which elementary sets values ​​could be attributed to the express numerically how much they claim about reality.