“Hostile symbiosis” is a concept I borrow from Benjamin Wittes. The idea is that the different human rights that are part of the system of human rights are both mutually dependent (or interdependent) and at the same time hostile to each other. For example, the publicity of free speech can’t exist without the privacy offered by privacy rights (no light without darkness), and yet at the same time respect for a person’s privacy may require limitations of someone else’s speech rights. Religious liberty can’t exist without equality of rights (religious liberty is in fact religious equality) and yet it may be necessary to allow religious groups the right to discriminate against candidate members in order to preserve their religious identity. And so on.
The same rights which are in one case interdependent and which can’t exist without each other, are in other cases mutually hostile and need to be balanced against each other and limited for the sake of each other. Hence the concept of hostile symbiosis.
Symbiosis is a term from biology, and is a combination of the Ancient Greek terms for “together” and “living”. It refers to close and long-term interactions between different biological species, the classic example being the clownfish and the sea anemone. A clownfish feeds on small invertebrates that otherwise have potential to harm the sea anemone and it’s territorial instinct protects the anemone from anemone-eating fish. In addition, the fecal matter from the clownfish provides nutrients to the sea anemone. The clownfish is in turn protected from predators by the anemone’s stinging cells, to which the clownfish is immune.
This is not a hostile symbiosis, as in the case of different human rights. Human rights form not just a hostile symbiosis but also an obligate symbiosis, meaning that both symbionts entirely depend on each other for survival. That is, as I understand it, not the case with clownfish and sea anemones, but some types of fungi and tree symbioses for example are obligate in nature. Many varieties of fungus live in close association with trees and other plants, drawing in nutrients from deep underground and providing them to the tree in exchange for a share of the energy (in the form of sugars) produced by the tree’s photosynthesis. The trees need the fungi in order to gain nutrients more efficiently (source).