Support One can never tell whether another person is acting from an ulterior motive; therefore, it is impossible to tell whether someone's action is moral, and so one should evaluate the consequences of an action rather than its morality.
The author concludes that one should evaluate the consequences of an action instead of its morality.
Why?
Because of an intermediate conclusion: it’s impossible to tell whether someone’s action is moral.
That intermediate conclusion is supported by a premise: it’s impossible to tell whether someone is acting from an ulterior motive.
There are gaps to be bridged between the premise and intermediate conclusion, and between the intermediate conclusion and the main conclusion.
Between premise and intermediate conclusion:
If it’s impossible to tell whether someone’s acting from an ulterior motive, then it’s impossible to tell whether that person’s action is moral.
Between the intermediate conclusion and the main conclusion:
If it’s impossible to tell whether someone’s action is moral, then you should evaluate the action based on consequences instead of morality.
Which one of the following ███████████ ██ ██████ ████ █████ ██ ███████ ███ █████████ ██████
The intention of ██ ██████ ██ █████████████ ███ ██ ██████████ ██ ███ █████████
The assigning of ██████ ███ █████ ██ ████ ██ ████ █████████ ██ ███ ██████████ ██ ███ █████ ██ █████ ████████
One can sometimes ████ █████ ███ ███████ ███ █ ██████████ ███████
There can be ████ ███████ ████ ███ ███ █████████ ██ █ ████ ███████
One cannot know ███████ ███████ █████ ███████ ██ █ ██████████ █████████ ██████ ███ █████ ████ ████████████ ████ ████████ ███████ ████