Using "eligible" correctly

Question

Is it standard English to use the adjective "eligible" for non-human entities?
Dictionaries seems to suggest that "eligible" should only be used with human nouns.

Answer 1

Short Answer

There are two entities involved in the concept of eligibility. One must be human-based and the other may be anything. (1) The entity that creates the rule for determining eligibility must be human or come from human-based systems. (2) The "eligible entity" doesn't need to be human.

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Longer Answer

The usage of eligible has the following characteristics:

• The entity that is or is-not eligible.
• The purpose for which the entity has eligibility.
• The rule or condition for determining eligibility.
• The person, organization, or social system which determines the rule/condition.

The entity does not need to be human. Store items purchased may or may not be eligible for return and refund.

However, a "human" or some "group of humans" (or in fiction, some intelligent agent) must determine (or document how to determine) if the entity is eligible for the purpose. The person, organization or social system that determines the rule or condition for eligibility is always ultimately related to a human based choice/determination - either directly or indirectly through a social convention, a contract, a policy, or a law. The only exception would be anthropomorphic perspective, AI, sci-fi, etc.

So a corollary to this would be that you could not have a sentence that uses "eligible" with absolutely no human basis. So pure natural-science, physical systems are not eligible to be described in terms of eligibility. Also, animals interacting with nature would not be described with eligibility.

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Exceptions

Some limited/narrow exceptions could be made for metaphors based on a social animal related to the social system of the species:

• OK: Eligibility of an animal to mate depending on social status.
• Not OK: A squirrel knowing it's not not eligible to step on a tree limb because the limb won't support it's weight.

Also, anthropomorphism can be used, but the result is still a matter of endowing non-human things with human qualities:

• The little rock wished that it would be eligible to enter the race. The mountain said, "all rocks larger than an acorn but smaller than a bear may enter the race." "Oh joy!" said the little rock, "I'm eligible to enter the race!" And at that moment, the little rock started tumbling down the mountain. Faster and faster, rolling at such a rate the little rock was getting dizzy! And then, all of a sudden, the tumbling stopped and was replaced with a great wind. "I'm flying!" said the little rock with sandy rock-tears of joy...

Also, technical fields will borrow words and use them outside their standard usage. So it might be found in something like (I'm making this up) a quantum physics particle being eligible for attachment to a molecule due to a required spin. But this is exactly what I'm saying is not how eligible is used in standard English.

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Justification for this answer.

This answer was largely based on original research. The conclusion that humans must be involved in creating the eligibility rule is based on me not being able to find any examples to the contrary after a large variety of searching on google, google ngram, and corpus searches.

Furthermore, if one could use "eligible" for a completely non-human, natural physical world context, then one would expect to find some examples such usage. Yet the following google searches come up with practically nothing:

• "the earth is eligible to"
• "the sea is eligible to"
• "the water is eligible"
• "the atmosphere is eligible"
• "the bear is eligible to eat"
• ""the dog is eligible to eat"
• "dogs are eligible to eat"

Please feel free to add a counter example in the comments, if you can find one! (It must be an example of real usage by someone other than yourself!)

Answer 2

Yes. The word eligible can be used for living beings other than humans and also for non-living things. Though it's interesting that the word is mostly used for living beings especially humans. +1 for the question :)

Here I found the authentic sources using eligible for the context in concern:

Eligible for non-living thing

Under the three definitions, a school is eligible to participate in all the FSA programs provided the school offers the appropriate type of eligible program - Institutional eligibility for Federal Student Aid Program.

Eligible for living being other than humans

Check out On Tap's official list of rules to see if your dog is eligible to participate - NBC Washington

Answer 3

In the definitions here the one that might have non-human application would be:

1) fit to be chosen; legally or morally qualified

which could refer to a non-human entity, as it does not specifically refer to humans.