Fuzzy on Fuzzy Logic

March 20, 2016

Sometimes, you just have to go “oy” about an article on rice cookers:

But it’s the math this one runs on, not the adorable music, that makes it so special. The rice cooker of my adulthood is built on fuzzy logic, a field of computing that tries to make rational decisions in a world of imprecision. By mimicking our gray matter’s ability to reconcile gray information, this frivolous gadget has become one of the most essential items in my kitchen.

This isn’t going to end well. This modern rice cooker is compared with her old one:

The Aristotle-inspired rice cooker I had in college would heat until the temperature of the rice rose above 212 degrees Fahrenheit, at which point all of the water would have been absorbed. As the temperature rose past this point, a magnet was activated by a thermostat and the machine would shut off. The appliance was either on or off, and it did but one thing while it was on.

And then we have the modern one:

In my current fuzzy-logic cooker, however, I tell the machine what kind of rice I’m using and how long it has been soaking. It takes that information and decides what temperature it should reach, and for how long. Generally using what are essentially if/then statements, it can fine-tune the process. For example, it can take into account the surrounding air temperature and turn the heating element up or down to compensate. The rice isn’t cooked or uncooked; the fuzzy-logic machine wants it to be cooked correctly.

The second machine might be better, but if this is what it is doing, it’s not using fuzzy logic. It seems to be using perfectly crisp logic. The machine has more than 2 states, but the logic needn’t have more than two truth values to capture those multiple states.

Now, I suppose it could be using some sort of fuzzy thresholds to determine when to switch, but I don’t see why it would bother. It’s going to determine temperature plus time. Both of these are going to be crisp. It’s going to be in a particular temperature for a given time (patch heating/cooling cycles of the element under control of the thermostat…but it won’t represent the heat that way!). Then it might switch to another temperature for a different time. It might change its program on the fly depending on sensor action.

But none of this is fuzzy logic in any sense.

To add a bit of pain:

Fuzzy logic was first proposed in 1965 by Lotfi Zadeh, a computer scientist who is now retired from the University of California, Berkeley.

Except multi-value and, in particular, infinite valued logic had been investigated before (c.f. Łukasiewicz-Tarski logic).

I doubt a correction will be forthcoming.

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