In the last couple years of the PhD, the only class I take is dissertation credit, which is in essence just doing research for my advisor. "Tuition" in this ca

In the last couple years of the PhD, the only class I take is dissertation credit, which is in essence just doing research for my advisor. "Tuition" in this case is arguably just an administrative device by which the university siphons some money off of my advisor's grants in exchange for the right to employ me as a research assistant. I guess the other side of the argument is that tuition represents the value of access to my advisor (which apparently fluctuates seasonally, cratering to zero during the summer...), and my advisor('s grant) pays me for my labor, and I (my advisor's grant...) pay(s) the university for access to for my advisor.