I needed help in comprehending the meaning of the concrete manifestations given below in the passage, and also the revelation part of the institutions
According to Spencer, society is a system of individual relationships. Institutions are recurring patterns of interaction with definite characteristics that can be identified and studied by the sociologist, apart from their concrete manifestations in particular cases. Social institutions are “real” in the sense that they reveal themselves to human consciousness as objective features of the external world. It is this objectivity that makes sociology and other social sciences possible.
Best Answer
"Institutions are recurring patterns of interaction with definite characteristics that can be identified and studied by the sociologist",
This describes what institutions have in common, the hierarchical structure, uniformity of rules and regulations for whatever particular purpose. Their "concrete manifestations in particular cases" refer to the specific examples of how they do their specialized, particular, work.
All government offices work in similar ways, but the DMV (for a driver's license) has different particular manifestations than the IRS for tax collection.
And a manifestation is the existence, reality, or presence of something, including a situation or relationship in an institutions. It is these relationships, felt and experienced, that are the "objective features of the external world".