–noun 1. the science that investigates the principles governing correct or reliable inference.
2. a particular method of reasoning or argumentation: We were unable to follow his logic.
3. the system or principles of reasoning applicable to any branch of knowledge or study.
4. reason or sound judgment, as in utterances or actions: There wasn't much logic in her move.
5. convincing forcefulness; inexorable truth or persuasiveness: the irresistible logic of the facts.
Whether one is logical does not mean that you are being rational. It reminds me of a question on Lenore Thomson's assessment that, "Logic is the art of going wrong with confidence." There may be logic behind things that the Bush administration has done for the past four years, however it does not mean that their actions appeared rational.
I pool all variables I can think of, variables are mulled for other variables, they are linked and cross referenced. I look at them and see which ones can be resolved. I then look at which ones are completely stupid. The last ones are those I find to be the most practical, those are what I decide on.
Reason as in using no feelings for decisions, of course, logic as in complex thought algorithms, um sort of, clear cause-consequence relationships, hell no, that's INTJ's contingency planning specialty, not ISTP's action adventure drive.
So the beginning of the statement is okay, the middle is further off, and the last bit is just a big no.
I've had people question why I've done something but then having explained my thought process it makes sense to them. I consider my decisions as reasonable more than logical. Sometimes it's just whether or not I feel like doing something at the time. Sometimes there isn't a whole lot of thought behind it. Depends on what's riding on the decision. Interpersonal decisions are made looking at the facts of a situation and coming to a conclusion then choosing an action that would best suit me.
I think this may depend at least partly on enneagram. Not all (or even most I think) ISTPs are the thrill-seeking, Se-bound types. Some are very, very dominantly Ti, and there's really no better word to describe them than logical. My brother is that way. Definitely ISTP, definitely logical and definitely puts logic (Ti) ahead of experience (Se).