Is "hence" repetitive here because of "since"?

Question

Because, since the common occurrences of life could never, in the nature of things, steadily look one way and tell one story, as flags in the trade-wind; hence, if the conviction of a Providence, for instance, were in any way made dependent upon such variabilities as everyday events, the degree of that conviction would, in thinking minds, be subject to fluctuations akin to those of the stock-exchange during a long and uncertain war.

In my opinion, it's not necessary because he said "since" before.

Answer 1

I think so, too. The part before the semicolon SHOULD be a complete sentence, but isn't. It would better be written "...the trade-wind, the conviction..."The writer wants to sound learned, but the writing is anything but revealing.

Answer 2

Hence used here is "therefore".  

Answer 3

I think so