It's been a useful model for me, but I am sometimes frustrated that it is not a heirarchical model. That is, we can't say (for example) that ethos supercedes pathos in importance. To answer that problem, I think we're supposed to turn to kairos, which suggests that circumstances of time and place, etc., determine which mode of persuasion is most effective.
But here's a current problematic example. I'm persuaded by the pathos of the left on the issue of healthcare. I feel great loads of sympathy for those who've struggled with huge payments and shady fine-print refusals and those kinds of things. I wish it didn't have to be that way. But on the ground of logos, I'm often convinced by passages like the following, from arch-conservative Walter Williams:
President Obama and congressional supporters estimate that his health care plan will cost between $50 and $65 billion a year. Such cost estimates are lies whether they come from a Democratic president and Congress, or a Republican president and Congress. You say, "Williams, you don't show much trust in the White House and Congress." Let's check out their past dishonesty.At its start, in 1966, Medicare cost $3 billion. The House Ways and Means Committee, along with President Johnson, estimated that Medicare would cost an inflation-adjusted $12 billion by 1990. In 1990, Medicare topped $107 billion. That's nine times Congress' prediction. Today's Medicare tab comes to $420 billion with no signs of leveling off. How much confidence can we have in any cost estimates by the White House or Congress?
So what do I do to make a decision about which "side" to support? Keep in mind, whether you disagree with my judgment matters little with regard to this question... ultimately, I'm just asking, what does one do when he's equally persuaded in different directions by different modes of rhetoric?