Perusoletus

Perusoletus is a term used in Finnish philosophy and logic to denote a foundational premise that is assumed without proof within a theoretical framework. The word combines perus, meaning base or fundamental, with oletus, meaning assumption or supposition. In this sense, a perusoletus serves as a starting point for reasoning and interpretation.

In practice, perusoletukset function as context-dependent commitments that enable deductions and explanations within a given theory or model. They are related to, but not identical with, axioms, postulates, or hypotheses. Unlike formal axioms in a deductive system, perusoletukset are often pragmatic or methodological statements about how the inquiry is conducted, what is being neglected, or what is taken as given for the sake of analysis.

Use of perusoletukset is common in scientific modeling, social science, and philosophical argumentation. Examples include assuming a system is closed, a variable is constant, or observers do not influence outcomes, not because these claims are empirically tested within the same argument but because they define the scope and tractability of the analysis.

Critically, perusoletukset shape conclusions and can introduce bias if left implicit or unexamined. Best practice is to articulate them clearly, justify their relevance, and revise them when necessary as part of methodological transparency.

In English-language discourse, the term is less common; translation often yields basic or underlying assumption. See also underlying assumption, hypothesis, axiom, and postulate.