More about Atheistic Nihilism,...and the Abacus

Technically, you can disbelieve in god/gods without considering yourself a nihilist. In practice most atheists have, either explicitly or tacitly, philosophies of physical monism and ontological naturalism. Here I am thinking of meaning in semiotic terms and not as a synonym for purpose. 
In order for something to have meaning it must refer to something else. It must call to mind something else. So for example, the beads of an abacus or lights on a scoreboard have no meaning until interpreted as a reference to quantities by a knowing subject. Likewise, a depictive painting is nothing more than smears of oil and dirt on a flat surface until the arrangement of colors calls to mind an image of something other than the painting itself. 

The foregoing atheistic philosophies assert that human experience reduces to a physical reaction. And physical things and processes have no meaning except those assigned to them by a knowing subject. This raises two questions. First, does the materialistic understanding of human nature satisfy the requirements of a ‘knowing subject’? Second, given a knowing subject, to what can the physical process of an individual’s live refer other than itself? I will leave aside the firs question and focus on the second. 

To me “knowing” applies to more than processes like complex data processing or reacting to sensible patterns. Such functions, as functions, can be adequately understood in terms of physical processes. Knowledge includes seeing things beyond what is immediately apparent, i.e. understanding what they signify. In the context of this discussion, the assignment of meaning happens when a particular instance represents a fuller, broader, and more general principle. In physical terms an architect can look at a crack and see it as a particular manifestation of thermal expansion and contraction. Not all references are physical. To what broader quantifiable physical process or state does the word “liberty” point? 

Some will say that these are just abstractions derived from experience of physical reality and have no reality apart from the mind. That is partly true. Everything we know, does indeed, ultimately come from our experience with sensible objects. That does not automatically entail that transcendent principles, like liberty, are not real. A physicalist generally has no problem with calling a particular action, like a falling apple, representative of something more universal and equally real, like gravity. What prevents you from gaining knowledge of transcendent principles within physical processes and things by means of observation? When people move freely across borders, this is a sign of their liberty. On what basis do you say that gravity is real, but liberty is not? True, gravity can be quantified in a way that liberty cannot. At the same time, I think it is a mistake to not include qualitative features in your assessment of what is and is not real.

Which leads me to why I think atheism is ultimately nihilist. When you say your life has meaning, you are assigning qualitative significance to what you consider a physical process. However that kind of qualitative assignment is precluded by the physical monism and ontological naturalism.