Jeffrey Thayne

In our age, science has attained a respected status that has largely gone unchallenged. I suspect there are many good reasons for this. Clearly, we have many conveniences today that we commonly attribute to the scientific endeavor. This is certainly a good thing. Brent Slife and Richard Williams believe that “it is important to understand how science has come to command such respect.”1 They explain,

The obvious answer is that science is persuasive. We are persuaded through scientific experiments that their results are trustworthy and accurate. The next question, of course, is why it is that scientific experiments are persuasive. When we look at the issue carefully, it seems clear that scientific experiments are persuasive because they follow the form and structure of a logical argument. The persuasive power of science, in this sense, is simply the persuasive power of logic.1

The relationship between logic and scientific discovery, Slife and Williams claim, “can be traced to Aristotle. It seemed to him … that following logical procedures is our best guarantee against unwarranted conclusions and errors in thinking.”1 A scientific experiment, they explain,

is essentially a logical argument. An experiment is set up much like a logical argument of the form “If _____ , then _____ .” Essentially, the researcher says, “IfI measure these certain variables in this way, and if I control for those other variables in this way, and if I make observations under these specified conditions, then I will observe that particular result.”1

The question we may ask is, “On the basis of observation, can this logical argument make any indubitable or genuine truth claims?” Let’s consider. Imagine we have a theory, and on the basis of this theory, we predict that we will observe a particular phenomenon under certain conditions. We do, indeed, observe the phenomenon as we had predicted. Can we then conclude that our theory is true? Let’s lay this out in the form of a logical argument:

If theory x is true, we will observe y.
We observe y.
Therefore, theory x is true.

This experiment is set up to verify a hypothesis on the basis of observation. Schooled students of logic will see an elementary fallacy in this argument, commonly known as affirming the consequent. The conclusion does not follow from the premises. The argument is invalid. Slife and Williams use a counterexample to show easily how this argument is fallacious:

If Socrates is a man, then he is mortal.
Socrates is mortal.
Therefore he is a man

“This is obviously not a good argument,” Slife and Williams explain, “because showing that Socrates is mortal does not necessarily show he is a man. He could be a dog or a bush or any other mortal thing.”1

Certainly, this does not mean our hypothesis is not true. We have certainly marshalled evidence in support of our theory. We just can’t claim to have proven our hypothesis. Can any scientific experiment make this claim? Slife and Williams continue:

That experimentation cannot prove anything true has been known for a long time. … The very way empirical studies are set up can always and only demonstrate the consequent. Thus, it is impossible—by the rules of logic implicit in the experiment itself—to prove any hypothesis true.1

It is not my intention here to “disprove” science, or to dismiss science in any way. I believe that well-performed scientific studies ought to be persuasive to us. My only goal here is to change the way we think about science. We can’t think of science as an indubitable, royal road to truth. In my next post, I will explain how a philosopher of science named Karl Popper proposed an alternative to the philosophy of verificationism, and I will also discuss some of the challenges of Popper’s point of view.

1. Brent Slife and Richard Williams, “Science and Human Behavior”, in What’s Behind the Research? Discovering Hidden Assumptions in the Behavioral Sciences (Thousand Oaks, CA: SAGE Publications, 1995), pp. 167-204.