Agreed Amos. But! (and there it is, the little driver of all things, so it seems :E)) But, the letters, the words, patterns and biases bare a subtle influence or stronger upon those otherwise godless works. Consider the word "electricity". There is a connection to the Greek word for sheep but what really does sheep have to do with a scientific word? Well it's front-loaded with science but it's roots are still embedded in antiquity. Of course the choice was made because of the earliest observance of electric phenomena was picking up static charge from wool to an amber rod. With the dawning comes morning and mourning become Elektra. :D sorry about that. Did you know that the word check, in every nuance traces back to the game of chess? It's true.

So, while we may divorce ourselves form belief in the divine we cannot deny the influence that the concept (think of all the words that have "-cept" [to grasp] in them) of divinity, be it Grecco-Roman of Jewish. It may be a question of degrees in the individuals' mind but it is inescapably there. And history demonstrates a not-so-subtle influence: holy wars, Crusades, Aryanism, Jonestown and the Hale/Bopp cult to mention just a few.

Along the line of the original question (...what is 'spirit'?) I find it most amazing that virtually every band and tribe on earth, no matter how primitive had a concept of spirit. Virtually universal.