Harry Frankfurt

"It is frequently insufficient to identify the motives that guide our conduct, or that shape our attitudes and our thinking, just by observing vaguely that there are various things we want. That often leaves out too much. In numerous contexts, it is both more precise and more fully explanatory to say that there is something we care about."

"Our natures are, indeed, elusively insubstantial — notoriously less stable and less inherent than the natures of other things. And insofar as this is the case, sincerity itself is bullshit."