Background There are three commonly known philosophical research paradigms used to guide research methods and analysis: positivism, interpretivism and critical theory. Being able to justify the decision to adopt or reject a philosophy should be part of the basis of research. It is therefore important to understand these paradigms, their origins and principles, and to decide which is appropriate for a study and inform its design, methodology and analysis.

Aim To help those new to research philosophy by explaining positivism, interpretivism and critical theory.

Discussion Positivism resulted from foundationalism and empiricism; positivists value objectivity and proving or disproving hypotheses. Interpretivism is in direct opposition to positivism; it originated from principles developed by Kant and values subjectivity. Critical theory originated in the Frankfurt School and considers the wider oppressive nature of politics or societal influences, and often includes feminist research.

Conclusion This paper introduces the historical context of three well-referenced research philosophies and explains the common principles and values of each.

Implications for practice The paper enables nurse researchers to make informed and rational decisions when embarking on research.