[datadrivenangel]

Exactly. All human systems are sociotechnical, and people within systems respond differently when they know that they're being monitored, and even more differently when they know that the monitors know that they know they're being monitored.

Exact models are somewhere between impossible and implausibly expensive for a non-trivial system. Approximate or die.

[bbor]

What’s not exact about a human brain…? Complex, sure. But I don’t see the difference in kind you allude to

[navaati]

It does not help you having a perfect and exact rule from initial conditions to future prediction... if you cannot have a complete and exact description of your initial conditions.

We might never be able to get this exact description of the internal state of a brain, this is what makes perfect prediction impossible.

[burnished]

As it turns out, pretty much everything. Individual neurons are imprecise and adaptive and they form networks that show chaotic behavior.

Basically I'd turn the question around - what makes you think brains are exact?