Hypothesis and Theory: Words do Matter!

By Krassimir Tzvetanov, Laurie Tyzenhaus
Thursday, March 26th, 2026

The terms hypothesis¹ and theory² are widely recognized, yet their precise meanings are often misunderstood. As a result, they are frequently used interchangeably - most commonly with theory being misapplied in situations where hypothesis would be more accurate.

A hypothesis is an initial idea - a working proposition or educated guess, which is intended to explain an event, phenomenon, or set of observations. It may be informed by anecdotal evidence, preliminary data, or logical reasoning. Hypotheses are typically developed in the early stages of the scientific or analytical process and serve as the foundation for designing experiments, collecting data, and evaluating outcomes. They guide inquiry while encouraging critical scrutiny through the search for both supporting and contradictory evidence. In this sense, hypotheses act as precursors to theories.

Crucially, a hypothesis must be formulated in a way that allows it to be tested and potentially disproven through empirical evidence - that is, it must be both testable and falsifiable.

When analyzing complex phenomena, multiple hypotheses may exist simultaneously. At the same time, numerous data points may relate to each hypothesis, creating a volume of possible combinations that quickly exceeds human cognitive capacity. In such cases, structured analytical techniques - such as Analysis of Competing Hypotheses (ACH) - are used to systematically evaluate and compare these possibilities. This method will be explored further in the next blog post.

In contrast, a theory is a well-substantiated explanation of phenomena, developed through extensive testing, observation, and the accumulation of evidence over time. Theories may also build upon or integrate other established theories. They evolve from hypotheses that have consistently withstood rigorous scrutiny and have been incorporated into a coherent explanatory framework.

Although theories are supported by substantial empirical evidence and often enjoy broad scientific consensus, they remain open to revision. On rare occasions, the emergence of significant new evidence may challenge and ultimately replace an existing theory, or even more an entire system of theories - a process known as a paradigm shift. Such events, however, are exceptional within the scientific community.

In intelligence analysis, theories are often constructed from limited and sometimes uncertain inputs, and even well-reasoned conclusions may ultimately prove incorrect. For this reason, it is essential to clearly document the theories and underlying key assumptions used in analysis, as well as the potential consequences if those assumptions are wrong. This enables decision-makers to adapt quickly and effectively as new information emerges.

In summary, a hypothesis serves as the starting point for systematic investigation. Through sustained testing and validation, a hypothesis may develop into a theory - a comprehensive, empirically supported model that explains observed phenomena. However, theories are not immutable; they can be revised or rejected in light of sufficient contradictory evidence. As described by Thomas Kuhn, such transformations - paradigm shifts - can fundamentally reshape understanding, as seen in the transition from Newtonian physics to Einstein’s theory of relativity.

Krassimir Tzvetanov

For the past six years, Krassimir Tzvetanov has been a graduate student at Purdue University, where his research focuses on homeland security, threat intelligence, operational security, and influence operations in the cyber domain. He also serves as Director of Security Engineering at Hydrolix, a high-performance log storage platform.

Krassimir has presented at numerous international security and threat intelligence conferences. He is an active member of the security research and investigation community, with contributions to multiple FIRST Special Interest Groups (SIGs). He also participates in the Honeynet Project and has been involved in several botnet takedown operations over the years.

https://www.linkedin.com/in/krassi/

Laurie Tyzenhaus

Laurie is actively coordinating and publishing vulnerability notes as part of CERT Coordination Center. She participates in several FIRST SIGs and is currently an Editor for the revision of International Standards, ISO 29147, Vulnerability Disclosure, and ISO 30111, Vulnerability Handling.

Prior to joining the SEI 13 years ago, Laurie was at the Department of Energy (DOE) as a member of the Intelligence and Counterintelligence Team for 12 years, working as a Technical Analyst. Prior to DOE, Laurie worked for 10 years at Argonne National Laboratory as the Associate Computer Protection Program Manager, leading Argonne's incident response team.