From Personalitypages ISTP profile:
I read this, and it occurred to me that the guy had a good point - I don't really know the difference between emotions and value judgments and don't have good criteria for distinguishing between the two.[ISTPs] do not pay attention to their own feelings, and even distrust them and try to ignore them, because they have difficulty distinguishing between emotional reactions and value judgments. This may be a problem area for many ISTPs.
So how can I tell them apart?
Also, when I distrust emotional responses, I'm not so sure that the reason is as above (because of failure to properly distinguish A from B). I can't verify this, however, until I get an idea of what he's really saying. In other words, it's unfair to rule out/modify a reason I don't understand fully.