Additional Premise Indicators

Aside from previously listed premise and conclusions indicators, there are
other argument indicator words you should learn to recognize. First, in
argument forms, sometimes the author will make an argument and then for
good measure add another premise that supports the conclusion but is
sometimes non-essential to the conclusion. These are known as additional
premises:
Additional Premise Indicators
Furthermore
Moreover
Besides
In addition
What’s more
Following are two examples of additional premise indicators in use:
1. “Every professor at Fillmore University teaches exactly one class
per semester. Fillmore’s Professor Jackson, therefore, is teaching
exactly one class this semester. Moreover, I heard Professor Jackson
say she was teaching only a single class.”
The first sentence is a premise. The second sentence contains
the conclusion indicator “therefore” and is the conclusion of the
argument. The first sentence is the main proof offered by the
author for the conclusion. The third sentence begins with the
additional premise indicator “moreover.” The premise in this
sentence is non-essential to the argument, but provides
additional proof for the conclusion and could be, if needed,
used to help prove the conclusion separately (this would occur
if an objection was raised to the first premise).
2. “The city council ought to ease restrictions on outdoor advertising
because the city’s economy is currently in a slump. Furthermore, the
city should not place restrictions on forms of speech such as
advertising.”
The first sentence contains both the conclusion of the argument
and the main premise of the argument (introduced by the
premise indicator “because”). The last sentence contains the
additional premise indicator “furthermore.” As with the
previous example, the additional premise in this sentence is
non-essential to the argument but provides additional proof for
the conclusion.