There is no such thing as "blind nature". That description suggests an attribute that doesn't apply to the natural world. Adaptation is non-random, as it is the result of objective criteria for fitness. Genetic variation might be random, but the natural selection that acts on that variation is not.So blind nature had no intent or reason for a pancreas appearing when the animal that preceded it had none? It was just another quirky anomaly and a crazy coincidence this organ had a valuable purpose?There is no argument to be made for the universe to have a reason for existence. That would imply intent. So yes, it is reasonable and rational to reject the idea that life and the universe are products of some underlying reason.
Nature is awesome. Especially when one considers there are trillions of evolutionary changes necessary for primitive species to evolve into much more advanced species. And with all of the millions of fossils science has found and identified, you would think we would have found thousands or tens of thousands of “failed experiments.” But does not seem to be the case at all.
And we might also find tens of thousands of transitional fossils between the more primitive species and the more advanced one? For example, if birds came from reptiles I would like to see hundreds of half winged creature fossils, not just that same old one that looks like the road runner (archeo...) they keep having to reproduce for all their text books.