Since:adverb – then, immediately after; from the specified time until now; at a time
between that time and now or that time and the time under consideration; ago, before:
conjunction - from the time that; during
or in the time subsequent; from the time in the past when; up to the present
time or the time being considered from the time in the past; the time when;
when; because, seeing that.
Because: adverb - for the
reason that; by reason of, on account of: conjunction
- for the reason that, inasmuch as, since; can also be used elliptically in
answer to a question, implying that a full response has been withheld; in order
that, with the purpose that.
Whilst these terms can be and, indeed,
often are used as if interchangeable, in writing it's probably best to stick to
'since' only when referring to time and to use 'because' to establish
causality. When 'since' is used to suggest cause it may make your reader to
stop to consider its meaning. Such pause for thought is not often something
you'd want to encourage.
'Because Frances wanted the
company of more than one animal in her home, she filled the place with cats,
dogs, rabbits and even a rather ancient and mangy donkey she'd discovered
wandering the streets.'
'Since Sandra stopped shopping
sequentially, she sought some significant substitute.'This is poor, as the reader doesn't know
whether the cessation of shopping was responsible for Sandra's search or
whether she merely decided to seek something different once she'd finished her
'Because Sandra stopped….' Is a
much clearer way of stating the former, I think; though it lacks the
alliteration, of course.
'Since mankind wandered out of
Africa and set up shop over the various continents of the world, the search for
commodities to buy has grown continuously.'Here, it's clear that we're referring to the passage of time between the
exodus and the present day.