If you see the validity of the point of view Knowledge, there are four different philosophies for validity of human knowledge.
- Conformity theory of truth
maintains that truth is what corresponds or conforms to existent facts of nature, the actual state of affairs and objective realities.
2.Coherence theory of truth
knowledge is valid if it is consistent and is in harmony with other ideas, statements or concepts.
- Pragmatic theory of truth
Everything in the world is relative, the worth of ideas, doctrine, principles, and practices depends on how they function in a given situation.
- Marxist theory of truth
“Truth is not in what it is, but in what it ought to be.” -Herbert Marcuse -Truth is achieved as a matter of practice or praxis.
Validity is the best available approximation to the truth of a given proposition, inference, or conclusion.
In 1963, Campbell and Stanley (1963) introduced the concepts of internal and external validity, and these have since been fundamental to educational research
- Conclusion Validity: there is a relationship between the two variables
2.Internal Validity: Assuming that there is a relationship in this study, the relationship a causal one
Campbell and Stanley understood internal validity as ‘ruling out any random circumstances’ and Denzin and Lincoln deﬁned it as the degree to which ﬁndings correctly map the phenomenon in question
3.Construct Validity: Assuming that there is a causal relationship in this study, we can claim that the program reflected well our construct of the program and that our measure reflected well our idea of the construct of the measure
External Validity: Assuming that there is a causal relationship in this study between the constructs of the cause and the effect, we can generalize this effect to other persons, places or times
Also, behind the notions of external and internal validity is the realistic ontology that strives to capture objective reality‘asitis’as much as possible(Denzin and Lincoln, 1994a, p. 5). That is why Denzin and Lincoln label these quality criteria as ‘Positivist’ or ‘Post-positivist’
Heidegger's Theory of Truth and its Importance for Quality of Qualitative Research, Journal of Philosophy of Education · April 2020
For validity of statement see famous logician Bertrand Russell paradox p.15
Bertrand Russell paradox: “If 2+2=5, then I am the Pope”
Viviane Durand-Guerrier, Truth versus validity in mathematical proof, ZDM Mathematics Education (2008) 40:373–384