For philosophy, nihilism is foremost the metaphysical nihilism, that is a nihilism in ontology and epistemology (there is no eternal ontological ground, in theistic terms, world doesn't have a creator, in any sense, and therefore has no unity as the world, this lack of unity, this unity is the concept of the world, therefore onlogical nihilism can claim that there is no world, just things).
I fail to see how metaphysical nihilism does not lead inevitably to moral nihilism. On what grounds do you establish morality. You can make rules codified into law reflecting the preferences of the majority but how can anything ever be right or wrong. At best you have the preferences of a majority or realistically the preferences of the ruling elite subject to change and personal expediency. What is the inherent significance of these rules? Nothing just transient strictures that carry a degree of risk if broken. If there is no world just things what does that say about humanity itself? Well we must simply be one more group of things with no real necessary value. If you can reach any other conclusion starting from metaphysical nihilism I am curious as to how.
This should not be confused with the simplistic claims that there is nothing, and we can't know anything as theists interpret it, but as its own metaphysical ground capable of producing rational ontology, epistemology and morals without succumbing to spiritualism. On this basis what we can say is that there is no intrinsic value, and therefore valuing is required as a finite process among other, susceptible to context and change, and because of that capable of progressing. To take values as fixed, therefore only blocks the potential progress of values and robs them of their rational basis.
Have you considered the possibility that the the end point of such a search the optimal rational ontology and morals may be ethical monotheism and if so the potential consequences of rejecting the optimum while searching for it. Ethical monotheism does not require a belief in spiritualism.
If people are not pushed a little into looking at the reality of God, they forget that they believe in God naturally, in the depths of their heart. Forget God, and you gradually forget life.
I don't agree with BADecker all the time especially with his literalism but in this instance he presents a very deep argument. In this thread I have cited multiple studies of fertility. These studies tell us that those who have rejected religion have a fertility rate below 2.1 the minimum needed for replacement of the population. Individuals who reject religion also report lower levels of health and wellbeing compared to the highly religious. Finally there is not a single current or historic non-religious group that has maintained reproductive replacement levels on the communal level.
There is a certain ironic elegance to a universe in which continued and sustained existence comes only to those who honor and respect its creator not via divine intervention but through inevitable cause and effect. Do we live in such a universe? It is entirely possible that we do.