As most people can probably recall from their primary school days, the keystone of the modern scientific method is the premium it places on verifiable, replicable experimentation, useful for investigation of the natural world. The outcomes of this experimentation are then used in an attempt to assemble a coherent theory that seeks to explain the mechanisms of the natural world. What differentiates the applied sciences from, say, the more abstract realms of pure mathematics and logic is the direct ability to investigate physical properties of the world that were predicted by prior experimentation. In this way, the practice of science is a cumulative and collaborative effort, and evidence, therefore, becomes its most valuable currency.
As our collection of knowledge about the natural world expands, so too does our gathering of evidence, which allows us to arrive at new conclusions. The essential question, however, that some may justifiably claim has been overlooked, is “What exactly is this ‘evidence’ that you are talking about?” For starters, I certainly cannot enumerate to you what exactly “evidence” is with absolute generality. I can instead show you instances of it, and I can tell you what it is not. And for our purposes here, we need not dash into the rabbit hole of the philosophical considerations of evidence, but rather examine its evident presence in the modern science.
This discussion of evidence comes on the grounds of a pertinent and exciting recent scientific development in the field of evolutionary biology. Biologists working in collaboration at both Michigan State University and the University of California San Diego have observed and documented the speciation of a virus into two incipient species in a laboratory setting, and in a duration of time short enough to observe its full effects. Speciation, which Charles Darwin proposed as the explanation for the multitude of differentiation in the “tree of life,” is the process by which one species gives rise to two distinct species due to evolution.
“Speciation has been notoriously difficult to thoroughly investigate because it happens too slowly to directly observe,” said Justin Meyer, a professor of biology at UC San Diego and a participant in the experiment. “Without direct evidence for speciation, some people have doubted the importance of evolution and Darwin’s theory of natural selection.”
In the experiment, the team used a virus known as “bacteriophage lambda,” which infects strains of the bacteria E. coli by attaching to receptors on the exterior of the bacterial cell wall and then infecting the cell itself. When the team introduced to the viral culture new bacteria that had two different types of receptors, it was observed that the virus specialized into two species that specialized in a receptor type.
“The specialized viruses were much better at infecting through their preferred receptor and blocked their ‘jack of all trades’ ancestor from infecting cells and reproducing,” Meyer said. “The survival of the fittest led to the emergence of two new specialized viruses.”
What is remarkable from this development is the amazing ability to observe, in a laboratory setting, something as elusive and seemingly distant as speciation. This development not only provides evidence in favor of evolutionary principles, but also simultaneously denies legitimacy of theories on the contrary. Of course, what remains to be seen is the replication of this experiment for its verification, but its principal findings are consistent with the accepted bodies of knowledge. Essentially, arguments reliant upon evidence are, to our knowledge, the strongest there are. Contrary to what certain groups may claim, evidence is not derived from authority, and is it not subject to agreeability. Hopefully, this instance can serve as an example of the importance of scientific evidence and the central role it plays in the advancement and promotion of knowledge.
