Luminous-intensity Memes

Okay so someone's out here fighting the good fight and I'm here for it. The candela (cd) is one of the seven SI base units, measuring luminous intensity, but here's the kicker: it's literally defined using other fundamental units. It's basically kg⋅m²⋅s⁻³⋅sr⁻¹, which makes it about as "fundamental" as calling a sandwich a basic food group just because you eat it every day. The candela is defined as the luminous intensity of a light source emitting monochromatic radiation at 540 THz (green light, where human eyes are most sensitive) with a radiant intensity of 1/683 watt per steradian. So yeah, it's derived from watts (power) and steradians (solid angles), which themselves come from more fundamental units. It's basically a unit that exists because humans decided "we need to measure light the way our eyeballs perceive it" rather than any actual fundamental physical property. This person is absolutely right to be upset, and frankly, we should all be joining them at this table. The candela is the imposter among the SI units, and it's time we had this conversation.