The boss asked me the other day whether it's more correct to say
In our business, change is constant.
In our business, change is a constant.
Both of these sound perfectly correct to me, which is what I told him; but there's a slight difference in meaning that I just can't seem to articulate. Help?
Definitions, not that they're much help:
constant (noun): a quantity that does not vary
constant (adjective): unvarying in nature; steadfast in purpose or devotion or affection; uninterrupted in time and indefinitely long continuing