

A New Fitness Value System - scottcha
http://hackerhmb.tumblr.com/

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jacques_chester
This is ... awfully vague stuff.

Tangentially, the question of "who is the fittest?" comes up from time to time
in various places. It's a fairly meaningless question of itself, but fully
explaining _why_ leads to roaming over stuff like multi-objective optimisation
problems.

Which is neat if you like that sort of thing.

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robodale
Isn't that what "fitness" is? At least in terms of aiming for a healthy body
and mind. Vascular, muscular, pulmonary...any and every area can be optimized.
I agree, that the blog post was vague - I didn't really get what he was
saying.

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jacques_chester
The hint was in my callout to multi-objective optimisation problems.

MOOPs generally don't have an optimal solution. There's a pareto front of good
solutions, but you have to decide what you value.

In physiological terms, you can't have it all. You need to make tradeoffs. The
adaptations for strength are competitive with adaptations for endurance, and
so on. You can't be very strong and easily run a marathon.

Now, suppose we decide to develop an index of fitness. Any such index could
only be tested according to specific _tasks_ , which introduces the problem of
task selection. Because you can quickly optimise those physiological tradeoffs
to maximise index performance. If for example your fitness index has lots of
running and swimming, endurance athletes will dominate. If there's lots of
lifting and pushing, strength athletes will dominate. Average it over all
possible tasks and I suspect the No Free Lunch Theorem will apply and everyone
will suck equally.

There is no "fair" index because the entire concept of "general fitness" is
nonsensical. All fitness is fitness for a task or group of tasks.

This is true of almost everything in life, because almost all the hairy
problems we face are about trading off multiple objectives. The important
lesson is learning that sometimes, you simply cannot have everything you want.

