Last September, while in Alaska, President Obama re-emphasized the need to counteract the effects of climate change:
“Climate change is no longer some far-off problem; it is happening here, it is happening now. We’re not acting fast enough. I have come here today, as the leader of the world’s largest economy and its second-largest emitter, to say that the United States recognizes our role in creating the problem, and we embrace our responsibility to help solve it.”
As you can see in the above quote, the President believes that men have played a role in creating a climate change problem.
But how can he be certain?
It seems like an important epistemological question. After all, much of the public—not just the President—appears to express certitude in the propositions that man’s activities have, or have not, caused recent changes in the global climate. A lot of money has been spent, and legislation proposed, on the basis that the claim “man’s activities have caused harmful climate change” is true. And according to those who believe this proposition, the consequences of disbelieving it could be dire.
Justifying one’s certitude about man-made climate change is not as simple as chalking it up to a matter of “Science.” The majority of those who affirm or deny climate change are not scientists themselves, and so only have a limited ability to wade through articles and books to discern what’s true from what’s false.
And even scientists—even, in fact, experts in the field of climate change!—do not have perfect knowledge when it comes to achieving certitude about the subject. Like the rest of us, they bring personal biases and principles to the table when they conduct or approve research. And like the rest of us, they are human, and only have a finite amount of factors they can take into account before they reach a conclusion.
Is this to say that we should avoid coming to a certitude about whether or not climate change is man made? Not necessarily. Without certitude, we would have difficulty undertaking any action, much less an action on climate change. But we should be aware of the sources of that certitude.
In his classic Grammar of Assent, John Henry Newman (1801-1890) undertook a realistic examination of how people come to assent to things as true, how they reach certitude. In most cases, Newman found that we affirmed something as true not through some rigid process of logic, but rather, through a convergence of evidence or an accumulation of probabilities. Of his theory of certitude in the Grammar Newman writes:
“I there speak of certitude as not a mechanical or compulsory effect, upon the intellect, of premiss and conclusion, but as a free act of the mind, following upon a judgment that such and such arguments and conclusions are deserving of such an absolute acceptance. And I maintain there, that these preliminaries of assent are, almost in every case, of the nature of probabilities, influencing the judgment to carry out the act of certitude, not separately, but by their cumulation.”
For instance, take the accumulation of probabilities that have led a boy to believe that a particular woman is his mother. Ever since he can remember, this woman has taken care of him. She has told him to call her “mom.” He has seen pictures of himself as a baby with this woman holding him, and has seen his birth certificate with her name on it. Now, it may turn out to be otherwise. He may discover in the future that she is not who she says she is, that she in an imposter who has kidnapped him from the hospital. But at this point, it’s still perfectly reasonable for him to be certain that this woman is his mother.
Now let’s take the hypothetical case of an average person—not an expert—who is certain that climate change is man made (we could do the same with someone who doesn’t believe in man-made climate change):
- Most of his science teachers in school believed that climate change was man-made.
- He has probably read some articles on climate change, perhaps some books, and watched some documentaries on the subject.
- He may have read some articles arguing against man-made climate change, but didn’t find these persuasive.
- Some other people he respects also believe that climate change is man-made—perhaps they’re friends, mentors, or people who belong to the same political party.
- The few people he knows who argue against man-made climate change also hold other positions he strongly disagrees with.
- He has also had the experience of the past couple of summers being unusually hot where he lives.
- He thinks the oil refinery that he drives by on the way to work is ugly and a blight on the landscape.
- He is very critical of those who have adopted a utilitarian attitude towards the earth and its natural resources.
These and most likely a multiplicity of other factors have led this hypothetical individual, and many like him, to come to a certitude that climate change is man made, and that the government should act to curb its effects. And, according to Newman’s reasoning, it may very well be a legitimate certitude, even if the reality of what the person assents to happens to turn out to be false in the future (not claiming here that it is false!). The above examination is not necessarily to critique how people like our President come to be certain that climate is or is not caused by man. If anything, it’s to simply show that coming to certitude (even about a scientific matter) is not a precise science, and to suggest that we exercise great caution and humility with the actions we propose based on that certitude, especially when it comes to actions on a national or global scale.