Scientific Consensus and Certainty

How Do Scientists Collaborate and Reach Consensus?

Although challenging other scientists' explanations of natural phenomena may seem unfriendly, it is actually a form of collaboration (working together). By reviewing and questioning each other's methods, data and findings, scientists not only improve their work, but they also communicate more effectively.

Peer-reviewed research Image Credit: AMS

The peer-review process serves as a quality-control check before scientific research is published. Scientists submit their research in the form of an article (or paper) to a scientific journal. Scientists in related fields (peers) read and evaluate the submitted article. After fellow scientists read the paper, they recommend changes to the author(s) that would improve the article or research. If the claims being made in the paper are not supported by the evidence presented, the article may be rejected. This step also helps to ensure that scientific papers are based on valid, empirically based research.

When the work being reviewed can be repeated and confirmed, then the scientific community is likely to reach consensus (agreement) and accept the findings and explanations as valid. If, on the other hand, scientists cannot confirm or validate the research, then those explanations or ideas are likely to be challenged, or even rejected. Challenges may also include proposing alternative hypotheses or explanations. The author–scientist may then test these new alternative hypotheses, or he or she may supply additional evidence to support his or her claims. The final goal of the process, however, is not to disagree but to revise the explanation so that the scientific community can reach a shared agreement (consensus).

IPCC Scientists Image Credit: Univ. of Miami

Once papers are presented at conferences or are published, the wider scientific community has an opportunity to review and challenge the research. The scientific ideas are evaluated against alternative explanations and the evidence is compared with competing evidence collected by other scientists. Acceptance of an explanation ultimately depends on which explanation describes the most observations in the simplest, most logical manner.


One example of extensive and international collaboration among scientists is the Intergovernmental Panel on Climate Change (IPCC). The World Meteorological Organization (WMO) and the United Nations Environmental Programme (UNEP) created this panel in 1988 to assess the present knowledge about climate change.

The panel is divided into three working groups. Working Group I assesses the latest understanding of the science of climate change. Working Group II assesses the potential effects of climate change on both natural and socioeconomic systems. Working Group III analyzes the options for avoiding (or mitigating, limiting or offsetting) the effects of climate change.

The IPCC involves thousands of research scientists at universities and laboratories throughout the world, but it does not fund new scientific research. Instead, IPCC scientists read the most current peer-reviewed, published scientific papers on climate change and assess these findings in comprehensive reports that are published approximately every 6 years. 

The first IPCC report was published in 1990 and the Fourth Assessment Report was publishedin 2007. There were 152 lead authors, more than 500 contributing authors, and over 600 reviewers who contributed to the fourth report (Houghton, 2009).

Scientists are currently working on the fifth report and Working Group I’s portion, The Physical Science Basis, was released September 2013. The other Working Groups will finish their reports in early 2014 and the final Synthesis Report is expected to be released in October 2014. You will learn much more about the IPCC and its findings in this program.


How Are Scientific Theories Developed?

Reaching consensus allows scientists to blend together the accepted findings of scientific research that have occurred over time. Hence, a scientific theory is the end product drawn from comprehensive research, combining all the most current, valid evidence to explain a wide range of phenomena (scientific observations). A scientific theory represents the most powerful explanation scientists have to offer.

For example, the theory of plate tectonics provides the best, most current explanation of how Earth's crust moves and why certain landforms and processes (earthquakes and volcanoes) occur in specific locations.

Is It a Law or a Theory?

Scientific laws describe specific relationships under given conditions in nature, but they do not explain those relationships. Sir Isaac Newton's third law of motion — For every action, there is an equal and opposite reaction — is a good example. Thus, laws are well-supported descriptions, whereas theories are well-supported explanations. One important point to remember is that theories do not become laws, and laws do not become theories.



How Certain Is Science?

Science communication Image Credit: Microsoft Clip Art

To summarize, the pursuit of science focuses on establishing probability rather than certainty. Scientists accept the fact that they are not all knowing and must remain objective and open to other possibilities when conducting scientific research.

However, through the use of consensus-building activities — challenging others' ideas, reexamining and retesting data, critiquing others' work through the peer-review process — scientists have been able to build a body of knowledge about which we can be reasonably confident. Still, there are scientific mysteries that are not yet well understood; conclusions about those are likely to have a much lower probability of accuracy.

Science is, therefore, simultaneously durable enough to provide a reasonable basis for scientists to make logical conclusions about the world in which we live and still flexible enough to be revised and improved when newer, better evidence and findings are discovered.