But isn't the same thing true for computers? 10 CPUs running the same calculations will show variations in time, heat distribution, etc...
But the differences are all masked by the fact that the ten CPU's only produce different results if there is a bug or malfunction. When there is no bug or malfunction, the calculations generated as output should all be identical. And, I guess I should explicitly state certain qualifications (which I assume are implicit in your premise), such as that presumably the executed programs don't sample hardware registers for the purpose of random number generation, generally speaking that the state of external devices to which they attach are functionally identical (e.g., network drives appear the same when they are accessed by the different computers), etc. And we're talking about digital computers, as opposed to analog, right?
On the other hand, in the case of people, the idea that different people do different things when confronted with the same situation (in what they they choose
to do) isn't a bug; it's a feature and it's expected as normal variation.
First of all, I realized that the fingertip needle example is lacking a bit, because it depends on so many variables like the pathways from fingers to the brain, the density of the receptors in the finger tip, etc...
But the result is always the same: the brain recognizes that a needle touched the fingertip.
The difference is speed of recognition, intensity, etc...
And that's what I meant with the CPU example as well. The RESULT of the calculation will always be the same. But there will be minor variations in each CPU regarding the calculation time, the generated heat, the amount of power needed, etc... that's just natural, because no CPU is exactly identical to the other, even when they come from the same assembly line.
And in human brains, this difference is even greater, because every human brain develops differently because of different outside factors. If you compared the brains of twins, you would already see variations in the processing. BUT the results
to a given input would always be the same.