In a recent article in the Chronicle of Higher Education, which was taken from his new book, Enlightenment Now, Harvard University psychology professor Steven Pinker challenges the “war on science,” which he blames on religious fundamentalists, right-wing politicians, and postmodernists. Now, there are certainly elements of Pinker’s approach that are commendable. Surely he is right that self-interested business and political interests sometimes motivate people to reject scientific findings that are not convenient for them. He is also correct to note that some people’s religious views influence their interpretations of nature.

I especially applaud his rejection of postmodernist views of nature, which construe truth and knowledge as nothing but subjective human constructs without any objective basis. Pinker is right that data should have more weight than our feelings in formulating our ideas about nature and society.

Unfortunately, however, Pinker’s overweening faith in science as a reliable path to the truth has its own problems. First, he seems to assume that “science” is a single, unified front, always striving for objective truth in the face of religious or philosophical obscurantism. However, although observation and experimentation are the crux of the scientific method, there are many different kinds of science, some more reliable than others.

Pinker wants to parade all the achievements of science before us — and they are certainly impressive — and then use that to validate everything that “science” says, as though everything that “science” says has equal validity. But this is a naïve vision of science.

For instance, in Pinker’s own field, psychologists are grappling with the so-called replication crisis (which is expanding to include other scientific fields, too). The problem is that many psychological experiments cannot be repeated, calling into question many psychological theories that were considered settled scientific facts just a few years ago.

Another problem that has dogged science through the ages is false assumptions that undermine scientific theories. For instance, in the 19th century it was considered indubitable that empty space was not really empty, but was composed of a substance called ether, through which light and other electromagnetic waves travelled. Today physicists consider ether a fictitious construct. At the time, however, it was considered solid science.

Pinker seems to think that scientists come to their observations, experiments and data with no assumptions at all, with — dare I say it — a blank slate. But Pinker should know better — just read his own book on The Blank Slate, where he argues that humans in general have hereditary intuitions and behaviors. In his recent article he states:

Cognitive psychologists have shown that humans are vulnerable to crippling biases and fallacies. Movements that aim to work around those biases and to spread scientific sophistication — data journalism, Bayesian forecasting, evidence-based medicine and policy, real-time violence monitoring, effective altruism — have a vast potential to enhance human welfare.

Somehow while acknowledging the problem of human biases, Pinker thinks that scientists can somehow magically escape from these biases and fallacies that beset other lesser mortals.

Another problem plaguing some kinds of science is that they involve significant extrapolations that may or may not prove to be valid. In the 19th century, Lord Kelvin, a brilliant scientist who contributed a great deal toward our understanding of thermodynamics, used extrapolation to determine that the maximum age of the earth is 100 million years. Scientists today consider his extrapolations a huge blunder. Why? Because he did not understand radioactivity and nuclear energy (nor did anyone else in his day). Scientists do not always take into account — or even know — all the factors in complex systems, so extrapolations can be misleading.

Finally, Pinker doesn’t seem to recognize that science is one path to knowledge among others. He appears to imply that science is the only reliable way to gain knowledge. But what can we make of the position — advanced by the famous British empiricist David Hume in the 18th century — that any knowledge that is not based on empiricism is invalid? This position is, in fact, self-refuting, because it is not based on anything empirical. It is a philosophical, not a scientific, statement.

In sum, Pinker’s ideal for science — the objective search for the truth that sets aside all assumptions, presuppositions, and biases in favor of observation and experimentation — is certainly laudable, and I agree with him that we should pursue this ideal. However, let’s not delude ourselves into thinking that scientists — himself included — can entirely lay aside all their biases and assumptions that color their ideas and theories. Science is a good thing, to be sure, but let’s not turn it into another religion by insisting that whatever is considered “consensus science” is always the gospel truth and anyone questioning the scientific consensus is a heretic worthy of scorn (or worse).

Richard Weikart is professor of history at California State University, Stanislaus, and Senior Fellow at Discovery Institute’s Center for Science and Culture; he is author of The Death of Humanity: And the Case for Life and Hitler’s Religion.

Photo credit: Steven Pinker, by Better than Bacon, via Flickr.