What does non-rivalry mean?

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Hello, I am interested in goods, material or non-material, that can be transferred from person A to person B without loss, such that after the transfer of X from A to B, both A and B now possess X (e.g. objects such as viruses, conditions such as illnesses, or knowledge such as a recipe). I thought there was a particular name for such goods but can't find it ... is there? Any pointers gratefully received. Also it seems to me that there is a sub-distinction between goods where what is transferred is the good itself (e.g. a mathematical equation) vs. something being transferred which is not quite the good, but is a necessary and sufficient precursor to its possession (e.g. virus particles for infectious disease, or seeds for plants). Is this a recognized distinction in economics?


The term you’re looking for is “non-rivalry.” Rival goods (in contrast to non-rival goods) are the standard stuff of economics: chairs, computers, etc. As you say, they are the kind of good where multiple people cannot use the good simultaneously without diminishing it in some substantive way. We can both try to sit on one chair, or share one computer, but we won’t be getting the desired experience.


Non-rival goods, on the other hand, are infinitely extendable. Knowledge and mathematical equations are great examples, since two people can enjoy them without diminishing the other’s use of it.

What about seeds and diseases? I think these are not as different from chairs and computers as they seem. Me and my neighbor can’t comfortably share the exact same chair, but if I was good with tools and upholstery (I am not), I could make use of the idea of his chair’s design and build my own. The idea is non-rival, but the specific chair is rival. Similarly, suppose my neighbor has some seeds for an unusual plant. We can’t both plant the seed; but if my neighbor is a good gardener, he can plant the seed, grow the plant, and eventually get me a seed that will contain basically the same genetic information as his original seed. Again, the knowledge is non-rival, in a sense, but the specific implementation is not.

I think you could say the same thing about diseases too, though we don’t normally think of people trying to produce and obtain diseases. Still, if I really wanted my neighbor’s cold, I could try to get some of his germs, but the specific germs would be rival – they’re in my body or his. But at the end of the day, we can still end up with the same symptoms.

The peculiar thing about seeds and germs is that they are, to some degree, self-replicating. In my opinion that’s a slightly different concept from non-rivalry, though it may sometimes have similar implications. 

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Last updated on July 26, 2022