Such modesty! It's actually worse than that. You could write a program for a feedforward thermostat (i.e. which tries to predict how much to heat or cool based on factors other than the room temperature, like the sunshine, temp outside, insulation, etc.) on your computer, but Powers et al. would scream bloody murder if you tried to use that as evidence that living systems are feedforward control loops!
You could write a program for a feedforward thermostat
Actually, you couldn't. At least, it wouldn't work very well, not nearly as well as a system that simply measures the actual temperature and raises or lowers it as necessary.
Try it and see.
"Feedforward control loop" is pretty much a contradiction in terms. Look at anything described as feedforward control, and you'll find that it's wrapped inside a feedback loop, even if only a human operator keeping the feedforward system properly tuned. There are some demonstrable feedforward links in the...
See this great little rationalist video here.