Social constructivism applied to science argues that an objective, observer-independent reality doesn’t exist, (or that if it does, it’s not accessible by humans, which is functionally the same thing). Under that framework, then whenever we talk about gravity, we’re not talking about some objective truth, but our attempts to model what we perceive as an objective truth. Hell, the only way we’re able to have this conversation at all is because I wrote “gravity is a social construct” and you understood what I was referencing enough to disagree.