It was this meaning of sensible, as applied to persons, that prompted Dr Johnson to say that it was used only in low conversation.
His ruling sounds unkinder now than it was then. Low talk, to us, is like the dodgy talk we get from the more desperate kind of comedian who resorts to it as a substitute for wit, as often found in the lateish evening on BBC Radio 4. For Dr Johnson, however, it was probably more a matter of social class than of bad taste: only ignorant people used the word in that way, he was saying. Or he may have meant little more than that it was all right for the coffee house but not for anyone who wanted to write good prose.
Whichever he meant, it seems surprising now. But then the usual definition of sensible was quite different in the 18th century. A sensible thing was something that could be perceived by one of the five senses - palpable is the word most people would use nowadays, from the Latin for to touch (and also to stroke, or flatter, but we never took that meaning).
And a sensible person was someone whose senses were acute enough to do the perceiving. It all came from sentire, which was the Latin for "to feel" and which also gave us sentiment. Sensible men or women were sensitive, as one would say today, to the feelings of others. They responded to the beauties of nature and wept at the deaths of friends.
Johnson would not have made his ruling 50 years later. By that time sense, having been about people's receptivity both to feelings and to ideas, had narrowed itself down and was now mostly about intellectual perceptions, and it had begun to take sensible with it. But sensibility stayed where it was, refusing to go along with the changes that had come over its near relations. So readers of novels were able to appreciate a clever little title such as Sense and Sensibility, which would not have made much sense to Samuel Johnson.
Though the older meaning of sensible is still to be found in modern discourse, I can't see it surviving much longer. Recipients of knighthoods and the like can say they are sensible of the honour without sounding too pompous, and Mr Blair was evidently sensible of the feelings of the electorate on the M4.
But I don't imagine that this was how he put it to John Prescott afterwards. When it comes to the distinction, often made by literary critics such as Dr Johnson, between the high style and the low, the People's Premier prefers the low.