Capitalism is a system where people are divided into workers and capitalists. Capitalists own the capital and hire workers who are paid according to their time. A scientist could be said to be a worker in a capitalist system. He or she will typically not have the capital to own large complex scientific instruments. Instead they are hired by capital owners which could part of the private sector or the public sector.

Either way the work a scientists does is no different from what you and I do. We are paid to do a job. So are they. Whether you produce something of value or not is a different matter. Unlike what many seem to assume, working in the private sector does not mean you create anything of value. Many corporate lawyers have freely admitted they produce nothing of value. Many pharmaceutal companies such as those making opiods have not only failed to create value. They deliberately brought harm to society.