Is Evolution a "Belief," or is it "Knowledge"?

I've heard many times, especially from scientists, that scientists don't "believe" evolution, they "know" it. I think this involves a bit of terminological confusion, and I think this confusion is bad for the overall discussion about evolution in the public arena. In this article, I'll briefly discuss why scientists do indeed believe in evolution and, in the process, say a few things about the nature of (religious) faith and its relation to knowledge.

Let's begin with the question "What is a belief?" The views that I'll articulate here are more or less well-established in the philosophical literature (i.e., I'm not presenting any wacky new theories!). According to many philosophers, a belief is an instance of something called a "propositional attitude." The idea here is that believing in something, first of all, involves a relation between two entities: (i) a cognitive agent such as ourselves and (ii) a proposition. Consider the statements, "I believe that Jesus was literally born of a virgin," "I believe that Joseph Smith spoke with the angel Moroni," and "I believe that photons are a kind of boson." In all these cases, you have an "I" on one side; this picks out an individual. On the other side, you have a proposition, which is introduced by the word "that": "Jesus was literally born of a virgin," "Joseph Smith spoke with the angel Moroni," and "photons are a kind of boson." Connecting these two is a particular kind of relation -- or attitude -- namely that of believing. This particular type of relation involves the individual holding that the proposition believed is an accurate or true representation of reality. There are other attitudes that one might have towards a proposition, e.g., "desiring that..." such and such is the case. But when one desires something, one is saying that he or she wants it to be true, whether or not it is. An individual believes a proposition when one thinks that it actually is the case in the world.

Thus, (some) Christians believe that God is three completely distinct persons who are also completely identical in essence. By believing this, they take the relevant proposition to -- like a geographical map being compared to Earth's land formations -- accurately correspond to the way reality is. The exact same goes for biologists, and this is why it's not at all wrong or misleading to say that scientists do indeed believe in evolution: biologists hold that the proposition that all species have a common ancestor from which they've descended with modification via natural selection and other mechanisms over a period of ~3.5 billion years is mappable onto reality without (a sufficiently problematic degree of) error. It is a belief that biologists have about this strange world in which we happen to find ourselves.

But there is more to say about this issue, because there are different types of belief, and not all were created equal! Consider the case of knowledge. Most philosophers take knowledge to be a species of belief. Why? Because on basically the only theory of knowledge that we have* -- one that originated with Plato some 2,500 years ago -- knowledge involves the cognitive assent to a proposition that is also true, and where this assent is justified by "good reasons." (Incidentally, the best theory of justification holds that "good reasons" amounts to "having evidence," where this evidence is preferably public, third-person checkable evidence; not the sort of mushy, subjective feelings that figure in "religious experiences.") So, the word "knowledge" picks out instances of belief in which the proposition is both true and evidentially justified. To say that one "knows" something is, therefore, to say that one also "believes" it. All cases of knowledge are also cases of belief, but not all cases of belief count as knowledge. This is precisely what makes knowledge a version of belief and not vice versa.

Thus, it would be much better -- much clearer and precise -- for scientists to say that they not only believe but also know that evolution is true, rather than contrasting these terms as if there's a tension between them or they're mutually exclusive. Yes, evolution is a belief; but not just any belief. It's one that appears to be true, and it appears to be true because there are mountains of empirical evidence from multiple domains that support it. Anyone with the proper education and technical instrument can check this evidence (i.e., it is "intersubjectively verifiable") if they have any doubts, and those who do check it almost without exception find their belief in evolution stronger after doing so.**

This leads to the issue of faith, which provides a very instructive contrast to knowledge. On the standard view, faith is also a species of belief. But rather than being belief which is both true and evidentially justified, the word "faith" picks out instances of belief in which the cognitive assent to a proposition is not sufficiently justified by the evidence, independent of whether the proposition is true or false. That is to say, whether or not Jesus really did ascend into heaven some two millennia ago, there doesn't appear to be any good, public, intersubjectively verifiable evidence to support the act of cognitively assenting to this possibility. Thus, this possibility must be assigned a low probability of truth -- it fails the test of "epistemic" reasonableness. As a result, believing this proposition counts as an instance of faith rather than knowledge. Strictly speaking, though, the Christian believes in Jesus' ascension just like the biologist believes in life's evolution. The difference is entirely justificatory in nature.

Now, something interesting follows from the above discussion. While the total evidence currently available to humans in the 21st century does indeed seem to support (by a long shot, in my judgment) atheism over theism -- and especially over elaborate theistic systems like Christianity and Islam*** -- it is just as possible for one to accept atheism out of faith as it is to accept the virgin birth of Jesus Christ by faith. The central question with respect to the issue of "epistemic" reasonableness is this: "Why assent to a given proposition P? What are the reasons that an individual can adduce for engaging P in the particular relation of believing?" If an individual becomes an atheist for the reason that "Richard Dawkins was such a dashing young man!" or "My parents raised me to be a non-believer," then the relation between the relevant individual and the proposition "God does not exist" isn't justified.

I think this is an important point, especially as more and more people around the world move away from religious worldviews. Such a demographic shift itself shouldn't immediately give atheists the warm fuzzies. As I've argued elsewhere, what the world needs today more than ever before in history -- given the destructive potential of the current genetics, robotics and nanotechnology revolution -- is not more atheists per se. Rather, what we desperately need are individuals who care passionately about ensuring that all the beliefs they hold are properly justified by the best available evidence. This is, indeed, what being rational philosophically means, and this meaning has nothing whatsoever to do with any proposition itself, whether it be "Allah is the one true God," "Jesus is both fully human and, at the same time, fully divine," or "photons are a kind of boson." To put this differently, being reasonable has everything to do with the why of belief and nothing at all to do with the what. As it happens -- and as stated above -- I do think the evidence strongly favors atheism over the alternatives; thus, being reasonable will quite naturally tend towards a secular worldview that excludes revealed "truths" accepted out of faith.**** But it's important to make this distinction: atheism itself isn't worth a darn thing if it's not arrived at by cognitive agents via the route of carefully considered checkable evidence. It follows that atheism "outreach" shouldn't focus on making people disbelievers, it should focus on being reasonable in all cases -- it should focus on good mental habits like thinking analytically. After all, empirical studies have demonstrated that analytic actually thinking leads to religious disbelief! (Indeed, if the evidence favored religion, then I'd be writing a post just like this one but on a religious blog and in favor of religion. But the evidence doesn't favor religion, so I'm an atheist. Epistemologically speaking, I care nothing about what I believe and everything about why.)

I hope this helped clear the waters a bit on the issue of belief, knowledge and faith. Faith and knowledge are just kinds of belief, and belief involves accepting a proposition as being an accurate "map" of reality. I'm very happy to hear what others have to say about the issue, though, so please feel free to comment below!

Written by Phil Torres ---

* This theory does indeed have problems, as a philosopher named Edmond Gettier pointed out several decades ago in a now canonical paper. But there just aren't any good alternatives on the marketplace of ideas.

** See page 110 - 111 of A Crisis of Faith for more.

*** See Chapter 11 of A Crisis of Faith, entitled "Theism Verses Theistic Religion: Which is More Improbable?," for details.

**** As some philosophers have pointed out, the views of rational individuals -- that is, individuals who put the why over the what will tend to converge over time. This is precisely what one sees in the domain of science: in contrast to religion, which is marked by widespread disagreement and mutually compatible views, science exhibits a truly remarkable uniformity of thought on the most fundamental of issues.