Physics offers no better word.
If you are quite sure. So when you say:
Nothing happens in a molecule without very tight controls.
for example, you are quite certain that there are no better words than control to describe what happens in a molecule? Are you quite sure?
The computer metaphor is clear.
Yes, it certainly is clear, that's precisely why I'm questioning it. Your use of the word 'control' could just be a very unfortunate word choice, but your use of the computer metaphor forces me to a much less charitable conclusion.
You can have hardware but it can't do anything productive without very complicated "instructions".
This gives me no option but to assume that we are talking about a traditional, serial computer with a nice clear distinction between software and hardware. In which case, of course. However, what you are now explicitly saying, that was only implicit in your word choice. is that this control is extrinsic. It comes from outside of the computer, in the shape of a program, a proper procedure that tells the computer what to do 'instructions'.
These "instructions" place the scope and limit on activity. They say what can and cannot happen.
Perhaps you can help me out though. Why exactly are you wrapping quotations around the word 'instructions'. I assume there's a reason. You are using the computer metaphor and so you are clearly describing the algorithm, the formal instructions that tell the computer what to do. What is it about this that makes you uncomfortable with the word 'instructions'. (Please don't let me catch you equivocating again...)
You can have a brain but it too can't do anything productive without "instructions", without "controls" on it's activity.
Sure, but in the case of a computer those controls are imposed on the software by the hardware. The instructions come from outside the computer. If you are convinced that this is a good metaphor then I guess you have to be committed to saying that the same is true of things happening in a molecule - that the controi comes from outside it (and indeed that the possibility exists that those controls could be changed; that we could reprogram a molecule if we were l33t enough. Obviously this is bollocks. A computer follows a program. molecules of water or indeed serotonin are not following an algorithm that is imposed on them as by a program. They are merely being what they are and
intrinsically playing out the consequences of the physical attributes they have in the situation they are in. The computer metaphor demands that we see control as
extrinsic, which is precisely the wrong way of looking at precisely the wrong word. Water in a pond tends towards the lowest energy state because of ......... not because it is following orders. (I'm still waiting for that pond description by the way...)
And since it is activity involving trillions of elements and the resultant phenomena is incredibly complex and long lasting the controls must be very precise and durable.
Not by very simple interactions giving rise to emergent behaviour without any extrinsic controls beyond each molecules intrinsic nature?