Postpositivism vs. Postmodernism: Core Differences Explained

Introduction to Postpositivism

There are laws or theories that govern the world, and these need to be tested, verified, and refined so that we can understand it. Thus, in the scientific method — the accepted approach to research among post-positivists — a researcher begins with a theory, collects data that either supports or refutes it, and then makes necessary revisions before additional tests are conducted (Creswell, 2003, p. 7).

Creswell (2003, p. 6) writes that post-positivist assumptions have governed claims about what warrants knowledge. Referred to as the "scientific method" or as "doing research," post-positivism is also known as quantitative research, positivist/post-positivist research, and empirical science. Post-positivism refers to the thinking that emerged after positivism, challenging the traditional notion of the absolute truth of knowledge (Phillips & Burbules, 2000) and recognizing that we cannot be "positive" about our claims of knowledge when studying the behavior and actions of humans. Post-positivism reflects a deterministic philosophy in which causes probably determine effects or outcomes (Creswell, 2003, p. 7).

Phillips and Burbules (2000) write that post-positivist assumptions include the following:

Core Assumptions of Postpositivism

1. Knowledge is conjectural (and anti-foundational); absolute truth can never be found. Thus, evidence established in research is always imperfect and fallible. It is for this reason that researchers do not prove hypotheses but instead indicate a failure to reject them.

2. Research is the process of making claims and then refining or abandoning some of them in favor of claims more strongly warranted. Most quantitative research, for example, starts with the test of a theory.

3. Data, evidence, and rational considerations shape knowledge. In practice, the researcher collects information using instruments based on measures completed by participants or on observations made by the researcher.

4. Research seeks to develop relevant, true statements — ones that can serve to explain the situation of concern or that describe the causal relationships of interest. In quantitative studies, researchers advance the relationships among variables and pose these in terms of questions or hypotheses.

5. Objectivity is an essential aspect of competent inquiry, and for this reason researchers must examine their methods and conclusions for bias. Standards of validity and reliability are therefore important in quantitative research.

Methodology: Critical Multiplism

Critical multiplism, as the methodology of post-positivism (Guba, 1990), is a form of methodological pluralism that utilizes both qualitative and quantitative methods. Creswell (2003, p. 7) notes that the knowledge developed through a postpositivist lens is based on careful observation and measurement of the objective reality that exists "out there" in the world. In this way, developing numeric measures of observations and studying the behavior of individuals become paramount for a postpositivist.

An assumption underlying this methodological pluralism is that researchers possess knowledge of the strengths and weaknesses of different approaches to research questions. Justifiable options are selected to complement limitations observed in the research conducted thus far (Cook, 1985), thereby ensuring that research questions are examined thoroughly from a wide variety of perspectives (Letourneau, 1999).