• Jean Piaget, 1967
• scientific knowledge is constructed by scientific community, and consists of mental constructs that try to explain experiences and measurements
• in this idea world is independent of human minds (so not solipsism), but knowledge of that world is a human / social construct
• it's opposed to objectivism which states that knowledge is independent of the learner

It is believed by constructivists that representations of physical and biological reality, including race, sexuality, and gender, as well as tables, chairs and atoms are socially constructed. Marx was among the first to suggest such an ambitious expansion of the power of ideas to inform the material realities of people's lives

— https://en.wikipedia.org/wiki/Constructivist_epistemology

• related to (or subset of?) relativism

  idea that views are relative to differences in perception and consideration

  — https://en.wikipedia.org/wiki/Relativism