What's wrong with 'Bananas are unable to grow in cold countries'? [duplicate]

Solution 1:

I'm afraid that you've run into an example premised on the "unable-versus-incapable" distinction, which our predecessors in the world of grammar and usage identified/invented a few generations ago. Eric Partridge, Usage and Abusage (1957) lays out the basic doctrine:

incapable connotes innate or permanent lack of ability; unable connotes inability 'in a specific situation or at a specific time': 'He is incapable of doing such a thing' and 'He is unable to do it'.

I think Eric Partridge was a brilliant lexicographer and one of the greatest experts on slang in the twentieth century; but this distinction is simply hooey. Assuming for the moment that unable means precisely "not able right now," how many things things can you say with assurance fall into the "not able ever" (that is, incapable) category? Would "bananas growing in cold countries" qualify? I don't think so. Without the benefit of a greenhouse and artificial lighting, bananas may not be able to grow in Iceland today, but I wouldn't bet my life on the proposition that they will never be able to do so (what with the possibilities opened up by genetic modification, for example)—or even that under certain conditions they couldn't do so now.

So what does that leave our incapable/unable distinction potentially useful for? Well, it might still apply to the statement "Chickens are incapable of laying crocodile eggs." But that raises the other half of the difficulty: Viewed from a narrow temporal framework—that is to say, right now—the proposition that "Chickens are unable to lay crocodile eggs" is clearly correct. They can't do so at the moment—and that objectively satisfies the requirement for unable, doesn't it?

The problem is that the "unable-versus-incapable" distinction seeks to divide the world into non-overlapping "can't right now" and "can't ever" categories, so that every "can't" phrase will fall into one or the other but not both. But in reality, there is a tremendous amount of overlap; in fact, you could plausibly argue that the "can't ever" option is entirely subsumed within the "can't right now" option. It is ridiculous to pretend that people started out saying "unable" only when they meant "can't right now but might be able to at some other time." A great many people have always used "[am/is/are] unable to" to mean simply "can't."

Bryan Garner, Garner's Modern American Usage (2003) is more than fair to the incapable/unable distinction in this entry:

incapable; unable. The words are basically synonymous, with perhaps a slight difference in connotation. Incapable suggests a permanent lack of ability {an incapable worker}, while unable often suggests a temporary lack of ability {I'm unable to accept your offer right now}. But these are hardly absolutes: if you're unable to lift 500 pounds, there's no implication that you'll ever be able to.

The crucial phrase in Garner's discussion is "often suggests." Attempts (such as the one by the purveyors of the "bananas" question that you've encountered) to draw a clear line between incapable and unable are based on a theoretical difference in usage that has virtually no counterpart in real life. Consequently, the rule will not help students or teachers gain greater insight into how the words are (and always have been) actually used by the vast majority of English speakers and writers.

Solution 2:

What's wrong with 'Bananas are unable to grow in cold countries'?

I may be drastically over-thinking this but, because the sentence (IMHO) seems to be grammatically acceptable, the problem must be one of semantics, if so then the issues would be:

1. Is the sentence unacceptable because it is semantically imprecise and therefore ambiguous?

What does “cold” mean in this sentence? Cold (adjective): 1) of or at a low or relatively low temperature, especially when compared with the human body low temperature, Cold (noun): 1) A low temperature; the absence of heat, especially in the atmosphere; cold weather; a cold environment.

What is meant by “countries” in this sentence? Countries (pl of country) noun: 1) A nation with its own government, occupying a particular territory; 2 (often the country) Districts and small settlements outside large towns, cities, or the capital; 3) An area or region with regard to its physical features (climate, terrain; geology, etc.). Definitions from Oxford Dictionaries online

2. Is the question semantically inadequate because not all bananas lack the ability, or are unable, to grow or to be successfully cultivated in cold countries?

Bananas in the Musa genus are native to Southeast Asia, and grow well in tropical and subtropical climates. Several varieties that evolved in higher elevations will survive colder climates, though few varieties will grow well in the cold. From SFGate.com.

3. Are the premises of the question erroneous? Is it wrong to confer the ability to grow upon a banana plant? Or does that ability more properly belong to human cultivators alone?

Able (adjective): 1) [with infinitive] having the power, skill, means, or opportunity to do something noun (plural abilities). Unable (adjective) [with infinitive] Lacking the skill, means, or opportunity to do something. Definitions from Oxford Dictionaries online.

At this point, from my perspective, the issue becomes philosophical rather than grammatical or semantic. As a layman I believe that plants do possess some degree of teleological capacity, but I understand that the conventional or orthodox scientific answer would be that teleology cannot be imputed to plants (banana or otherwise) and therefore a plant cannot be said to possess ability.

After considering each of the above possibilities I will hazard a (slightly) educated guess: the sentence is wrong because banana plants lack the ability to grow in cold countries independent of human cultivation.

Solution 3:

I would say that bananas don't have "abilities." So I wouldn't refer to whether or not they are "able" to grow in cold countries.

A better sentence is, "People are unable to grow bananas in cold countries." That puts "bananas" in the "object" space, where they belong, and gives the "ability" to some-thing/one else.