The Limitations of ScienceOpponents of science often argue that science could be wrong. “Science can’t explain everything,” is one such popular claim by those who attack science.  

Recently, a friend and I were discussing some new psychology research when he asked, “Are there any definites in psychology?”  I answered by telling him there are no definites in psychology or any other branch of science.

Some people make the erroneous assumption that science claims certainty, when in fact, science makes no such claims.  Scientific knowledge is tentative, and the tentative nature of science is one of its strong points. Science, unlike faith-based belief, accepts the preponderance of evidence and changes its stance if the evidence warrants. 

Science takes us where the evidence leads.

“The real purpose of the scientific method is to make sure nature hasn’t misled you into thinking you know something you actually don’t know.”
–R. Pirsing, Zen and the Art of Motorcycle Maintenance
(Gilovich, 1991, p.185)

The scientist has the attitude that there are no absolute certainties. R.A Lyttleton suggests using the bead model of truth (Duncan R & Weston-Smith M, 1977). This model depicts a bead on a horizontal wire that can move left or right. 0 appears on the far left end, and a 1 appears on the far right end. The 0 corresponds with total disbelief and the 1 corresponds with total belief (absolute certainty).

Bead Model of Truth

Lyttleton suggests that the bead should never reach the far left or right end. The more the evidence suggests the belief is true the closer the bead should be to 1. The more unlikely the belief is to be true the closer the bead should be to 0.

Adequate knowledge in area of scientific thinking helps one to understand evidence and assists with the ability to resist falling for nonsensical claims.  The more one learns about scientific thinking the more one becomes aware of what is not known, and the more aware one becomes of science’s tentative nature. Science is not about the need for closure, but about the need for establishing principles that are open to change.

Proper use of the scientific method leads to epistemic rationality (holding beliefs that are commensurate with evidence).  Relying on science also helps us avoid dogmatism (adherence to doctrine over rational and enlightened inquiry, or basing conclusion on authority rather than evidence).

The scientific method is the best method we have for learning about how things work in the observable universe.  Sometimes, science doesn’t get it completely right, but science does not claim absolutism, nor does it claim to have all the answers.

I have heard some people say, “Science doesn’t matter, what matters is what happens in everyday life and the real world.”  

News flash: the scientific method is the very best we have for understanding everyday life and the real world.


Duncan R & Weston-Smith M. (1977) The Nature of Knowledge by RA Lyttleton. The Encyclopaedia of Ignorance. Pergamon Press.

Gilovich, T. (1991).  How We Know What Isn’t So: The Fallibility of Human Reason in Everyday Life.  New York: The Free Press.

Hale, J. (2009). Scientific and Nonscientific Approaches to Knowledge.
(Accessed March 2, 2011)

Photo by Horia Varlan, available under a Creative Commons attribution license.