This thread is meant to find agreement on what the scientific definition of random mutations is within the domain of science and the philosophical boundaries that this definition resides within. Random mutations are one of those topics where misunderstandings are common, both from a scientific and theological point of view. In fact, my understanding of these concepts could be wrong, so I encourage feedback from biologists and laypeople alike. I am hoping that we can have a productive conversation that seeks to find common ground (as much hope as one can have on an internet discussion forum ).
From my understanding, random mutations are random with respect to fitness. This means there are no scientifically established general mechanisms whereby the organism can sense an environmental challenge and mutate a specific base in a specific gene to overcome that challenge. Instead, the processes that produce mutations appear to be blind to the needs of the organism. This is exemplified in the plate replica experiment described by Joshua and Ester Lederberg in their paper from 1952:
In that experiment they started with a single bacterium which then went on to found all the populations they used in the experiment. This is important to note because if the mutation were present in that founding ancestor then it would be present in nearly all of the descendants. Without going into the specific of the experiment, what they observed is that some of the bacteria in the experiment were resistant to antibiotics, a trait not found in the original ancestor. What they also found was that the mutation occurred without the bacteria being exposed to antibiotics. In other words, the mutation wasn’t caused by exposure to antibiotics and did not appear to be affected by the needs of the bacteria. The same conclusions were reached by Luria and Delbruck in their fluctuation assay in 1943.
I mention the dates of these papers, 1952 and 1943, for a reason. The structure of DNA was discovered in 1953, a year after the Lederbergs concluded that mutations were random with respect to fitness and a decade after Luria and Delbruck’s work. Random was not defined as being an even distribution of base changes along a stretch of DNA. Random was not defined as all substitutions being equally probable. Nobody even understood what mutations looked like at a molecular level at that time, but they still concluded that mutations were random with respect to fitness because it had to do with the relationship between mutations and the environment.
There are also exceptions that prove the rule. CRISPR/Cas9 is a really good example. In this system, the bacteria specifically alter their DNA to acquire immunity to specific phage. However, this mechanism is very limited in scope and can’t explain the vast, vast majority of mutations that occur throughout biology.
These are all scientific conclusions, and it isn’t meant to be a Truth with a capital “T”. Science is necessarily limited in its philosophical scope. All science can say is that there is no statistical signal linking mutations to the needs of the organism. This scientific concept and guidance by God can easily coexist, as many on this site have discussed. There is no way that random can be construed to mean no God or no guidance by God.
Please correct any science errors you think I may have made, and please try to find any common ground you think exists. Thanks!