Ted Cruz’s argument that climate change is a hoax to justify a government takeover of the world is absurd. But Bernie Sanders’s argument that “toxic waste byproducts of nuclear plants are not worth the risks of the technology’s benefit” might also be damaging.

Highlighting the left’s biases may seem like a pointless effort to apportion equal blame along ideological lines. But it is critical to understand how they have come into being. It suggests how difficult it will be to overcome our scientific and technological taboos.

Research suggests that better scientific knowledge will not be sufficient, on its own, to overcome our biases. Neither will it be mostly about improving education in STEM fields. To defeat our scientific phobias and taboos will require understanding how the findings of science and their consequences fit into the cultural makeup of both liberals and conservatives.

Joel Mokyr at Northwestern University, an expert on the history of science and technology, notes that the ease with which people accept scientific knowledge depends on how straightforward the proof is.

Einstein’s theory of relativity was readily accepted despite the fact that few people understood it because there were a couple of experimental results no other theory could explain. Natural selection is trickier.

“It is awfully hard to find a smoking gun” to prove evolution, Professor Mokyr told me. “This is by definition because the process is so slow.”

The evolution of scientific knowledge is messy, too. It does not neatly converge on truth along a smooth line, but rather jumps around as new knowledge disproves old certainties. Scientists’ understanding of the speed, intensity and implications of climate change is substantially different from what it was only a couple of decades ago.

But perhaps the most important snag to the diffusion of scientific knowledge is motivation. The average American has little at stake riding on whether the general theory of relativity is right or not. Evolution, by contrast, is a body blow to evangelical Christians’ worldview.

Only 48 percent of respondents agree with the proposition that humans evolved from other beings, according to the General Social Survey, a broad survey of American attitudes and beliefs. But when the question is prefaced with the qualifier “according to the theory of evolution,” agreement with the proposition rises to 72 percent.

Responses aren’t necessarily driven by ignorance. “Where there is a sacred value that empirical science contradicts,” science will have trouble making headway, notes Jonathan Haidt, a social psychologist at the Stern School of Business at New York University.

And the value doesn’t even have to be sacred.

A few years back, Dan Kahan of Yale Law School, Hank Jenkins-Smith of the University of Oklahoma and Donald Braman of George Washington University Law School performed experiments testing how values affected people’s agreement with scientists about climate change, the disposal of nuclear waste and allowing concealed possession of handguns.

“The problem, it seems, is not that members of the public are unexposed or indifferent to what scientists say,” they concluded. “They disagree about what scientists are telling them.”

People identified as more egalitarian and more open to government interventions to address social ills — the left, as it were — were much more likely to say that most scientists agree global warming is happening and that it is caused by human activity. Most also said scientists either disagreed or were divided on the safety of storing nuclear waste.

On the right, people identified as individualistic and wary of Big Government responded differently: In their view, the scientific consensus said the opposite. How could they think that? They manufactured the expert consensus they wanted by defining as experts only those who agreed with their ideological position.

It is not hard to figure out the biases. People on the right tend to like private businesses, which they see as productive job creators. They mistrust government. It’s not surprising they will play down climate change when it seems to imply a package of policies that curb the actions of the former and give a bigger role to the latter.

On the left, by contrast, people tend to mistrust corporations — especially big ones — as corrupt and destructive. These are the institutions bringing us both nuclear power and genetically modified agriculture.

“When science is aligned with big corporations the left immediately, intuitively perceives the technology as not benefiting the greater good but only benefiting the corporation,” said Matthew Nisbet, an expert on the communication of science at Northeastern University.

So when assessing the risks of different technological options, the left finds the risk of nuclear energy looming the highest, regardless of contrary evidence.

This doesn’t affect only beliefs about climate change and energy policy. The research identified similar distortions in people’s beliefs about the scientific consensus on the consequences of allowing concealed handguns. Biases also color beliefs in what science says and means across a range of other issues.