Murray Smith writes:
Friday afternoon in the car I heard a radio news report about the closing of an art gallery on Boston's tony Newbury Street. The reporter had interviewed the gallery owner and learned that due to economic conditions gallery sales had been down forty percent the last two years. Now the landlord was imposing a thirty percent rent increase, and the owner was throwing in the towel. The reporter concluded, "The decision was academic; she had to do it." The intonational profile showed that the second clause was a gloss on the first. I was surprised, not having heard this use of "academic" before. I have always understood "academic" in this sort of context to mean something like "without significant consequences".
Murray's understanding corresponds to the OED's sense 5 of academic, glossed as "Not leading to a decision; unpractical; strictly theoretical or formal. Now also in weakened sense: of no consequence, irrelevant." This sense itself presumably developed out of an implicit opposition between theoretical (= academic) and practical questions, whereby a discussion or decision that is "purely academic" is one that is purely a matter of abstract theory, with no immediate implications in practice — say because there are no relevant cases under consideration, or because the participants have no power to implement any decisions.
This sense appears to date from the 19th century: the OED's first citations for sense 5. are these, of which only the third strikes me as clearly an instance to Murry's common modern "without significant consequences" sense:
1812 Monthly Rev. 69 492 His erudition must be worked into the edifice, not exhibited in lumpish disconnection. He must preserve the epic form, without sliding into academic discussion.
1844 J. Keble Lect. on Poetry I. xvi. 315, I certainly hope you will not suppose that this is merely a lifeless and academic discussion. It is, believe me, of the greatest importance that the limits of imitation should be carefully and judiciously laid down.
1886 Times 31 Mar. 7/2 This discussion partook of an academic character, for it was well understood that, whatever the result of the discussions might be, no practical step would be taken in the present Parliament.
1897 D. G. Hogarth Philip & Alexander of Macedon i. 85 Since the references‥to the Olynthian war are in the last degree meagre and vague, and those to Philip merely general, the Olynthiacs would possess for the historian only an academic interest.
When I got home, I realized I had an opportunity for a breakfast experiment, even though it was mid-afternoon. Among the first baker's dozen hits on "decision was academic" in Google Books, three fit the unfamiliar usage.
In The Carrier, Holden Scott writes: "At the end of a similar hallway was a starirwell, lit by fluorescent strips of light. He knew by instinct that this was the right direction. … He reached the stairwell, shutting the glass door behind him. Cement steps led up and down, and again the decision was academic." Here, the decision apparently has important consequences, but the decider knows what to do without reflection.
In Sink the Shigure, R. Cameron Cooke writes: "As he stuffed the fourth stack of bills into his shirt, a deterring thought suddenly came to mind. What if the ship wasn't sinking, after all? Someone would later discover that the money was missing. … Men were shouting. Someone was coming this way. His decision was academic now. In a matter of seconds, he removed every stack of bills from his shirt, crammed them all into the aluminum box, and shoved the box back into the safe."
The third example shows, I think, how the use of "academic" could have slid over from "without consequences" to "automatic" or "obvious". In Howard William's book, A Year in the Life of Peartree House B&B, he writes: "Indeed, that night we had several others seeking accommodation — and for the first time I had my doubts about the desirability of having some people in the house, but the decision was academic as we were already full."
I agree with Murray in finding it odd to describe an obvious decision of significant practical import as "academic". But if the core meaning of this sense involves a question where reasoning or discussion has no practical consequence, then such cases ought logically to be included. A discussion or deliberation might be "academic" because there's no relevant case in view, because those discussing or deliberating have no power or no intent to influence the outcome — or because the answer is so strongly determined by current circumstances that no amount of deliberation could affect it.
The results of Murray's experiment still surprise me, as they surprised him. It would be interesting to look at the history of academic = "theoretical rather than practical". There are several different issues here: among them are the origins and popularity of the underlying theory v. practice opposition; the use of the word academic in this connection; and the distribution of the various reasons for impracticality. Some day, when we've got better standards for stable distinctions among word senses, better sense-disambiguating software, and better sense-tagged historical text collections, such experiments will be easier.
Will these experiments still be purely academic? In some cases; but in fact, legal decisions of considerable practical weight often hinge on the question of how particular words or phrases were used at a particular point in time, and what writers and readers would then have taken them to mean in a particular context. And several technologies of increasing importance depend on at-least-approximate answers to related questions about current usage.