ASEBL Journal – Volume 11 Issue 1, January 2015
In every system of morality, which I have hitherto met with, I have always remarked, that the author proceeds for some time in the ordinary ways of reasoning,
and establishes the being of a God, or makes observations concerning human affairs; when all of a sudden I am surprised to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with an ought, or an ought not. This change is imperceptible; but is however, of
the last consequence. For as this ought, or ought not, expresses some new relation
or affirmation, ’tis necessary that it should be observed and explained; and at the
same time that a reason should be given; for what seems altogether inconceivable,
how this new relation can be a deduction from others, which are entirely different
from it.8
Although Hume’s use of the double negative (“no proposition not connected”) may be
confusing out of context, he is universally understood to have meant that “it seems
inconceivable that a moral conclusion can be a deduction from premises that are entirely different from it.”9 In short, there can be no ought from is; at least not directly
by using logic alone.
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