No it just means that for selection to drive an increase in complexity, the individual steps that increase complexity have to be adaptive. Evolution isn’t a theory that says an increase in complexity is always adaptive, just that it some times is.
The LTEE is a simple environment where many natural challenges faced by E coli have been removed, and the primary selection pressure is variant growth rate, and the chief barrier to bacterial growth rate is genome replication time. The resources in the flask environment also run out significantly before daily passage, so any resource directed to expressing a locus that doesn’t contribute to growth rate is strictly wasted.
So the experimental setup indirectly rewards deletions, inactivation, and loss of function mutations in genes and loci that don’t contribute to growth rate (many of them genes that are unnecessary in the simple flask environment but would have provided a surival advantage in E coli’s natural environment).
But that means a key selection pressure found in natural environments, survival through different types of challenges, gaining the ability to metabolize novel compounds, combating parasites and predators, and so on, are either strongly diminished or in many cases entirely absent in the LTEE.
The LTEE is not an experiment aimed to ascertain what selection pressures drive increases in adaptive complexity or innovation. You can’t draw grand conclusions about what selection can or can’t do from it.
As Rum notes, the lab environment is not the natural environment. The “decay” in fitness relative to that natural environment occurred the moment they were placed in the lab environment. Changes in the lab environment are adaptive to the new environment.
Does the emergence of a macroscopic multicellular lifeform count?
Does niche partitioning in multicellular lifestyles, specifically showing differences in adaptation towards growth rate versus survival specifically, count?
What exactly defines “complex adaptation” if these examples don’t count in your opinion?
On a related note it’s not false that relaxed selection can provide the opportunity for increased complexity. In some cases it’s true selection isn’t the driver for the complexity, and the complexity might not even be adaptive, at least to begin with.
But the gains in (for example) genomic complexity resulting from something like insertions by transposons, and whole genome duplication, can in turn provide lots of opportunity for innovation as more mutations are allowed to explore the sequence space around existing genes. If this innovation is adaptive, selection is at least retaining the useful complexity. This might not be the kind of positive selection-dominated change that creationists (and adaptationists) like to think about, but it’s still evolution, a gain in complexity, and one where natural (purifying) selection plays a role.
It’s almost like Sal has partially discovered aspects of modern evolutionary theory, which has moved well beyond the sort of hyper-adaptationist ultra-Darwinism he seems to have in mind.
Edit:
Then his problem seems to be the dichotomous thinking again. Where if selection isn’t always the driver of complex adaptation, then he appears to think selection could not ever be a driver of complex adaptation. And it’s pointless to focus on that kind of hyperadaptationism anyway, since we still know of mechanisms that can drive up both complexity, and adaptation, though they’re not necessarily correlated or dependent on each other.