>If certainty has not been achieved, then you should remain skeptical This is like saying you should be skeptical of all scientific claims. But such a claim is

>If certainty has not been achieved, then you should remain skeptical This is like saying you should be skeptical of all scientific claims. But such a claim is in tension with the obvious successes of science and engineering despite the inherent tentativeness of scientific conclusions. Clearly we need something more nuanced. We can draw tentative conclusions and move forward with knowledge while also acknowledging the tentative nature of said knowledge. Global skepticism regarding all scientific results is paralyzing. >The studies that determined this used datasets from wealthy Western countries that are more ethnically homogeneous than average. It has to be for any such measure to be meaningful. For example, if you put a toddler in a box and starve it to death, its development stops completely. But this doesn't mean that environmental influence is 100% for all phenotypes. Heritability is a blunt measure for something highly multidimensional. As such, care must be used in its interpretation. What heritability tells us is that given similar environments, what variation in measurable traits is due to variation in genetics or variation in environment. An ideal measure of heritability is a function of environment and would be proportional to the rate of change of environmental influence at every step change in environment. Of course, such a measure is impossible and so we're left with our current blunt measure. But we can reason about some features of the ideal measure. For example, environmental influences have diminishing returns, thus there comes a point at which the rate of change of environmental influence is zero, meaning better or worse environment has no bearing on the trait and genetic variation dominates outcomes. On the other extreme, environmental influences are dominant. The relevant questions for the validity of heritability is whether the rate of change of environmental influence is steep at the current average environment. If it is steep, then it invalidates drawing conclusions based on measured heritability as the value is unstable. But your point about Dutch average height does not bear on this. The heritability measure is blind to global average changes in quality of environment. The fact that average height grew so substantially implies that the average environment changed substantially over that period. The Flynn effect is another example, where the average IQ across the population grew substantially over a similar time period. But this doesn't have any direct relevance to the heritability measure of IQ. The question is whether current measures of heritability are stable for typical variations in environment. Regarding height, I would guess yes as calories are abundant in the western world, even among the poor. >You are literally invoking a textbook ad hominem fallacy. Notice the word fallacy. Identifying logical fallacies by name is to help recognize patterns of invalid arguments. Ad hominem is only relevant if the argument is not valid. But my point a vacuous conceptual framework leading to specious conclusions is a valid argument.