'For' and 'Because': A Linguistic Bagatelle

My sense of the English language tells me that (1) below, but not (2), is good English.

1) On presentism, what no longer exists, does not exist at all. For on presentism, only the present exists.

2) On presentism, what no longer exists, does not exist at all. Because on presentism, only the present exists.

As I see it, (1) is good English because 'for' in a context like this means 'it is because.'