But the chances of acieving such a shared view become poorer when we try to encompass broader purposes, and to involve more people. This is precisely why the question is becoming more relevant today: the thrust of technology is to foster interaction among greater numbers of people, and to integrate processes into monoliths serving wider and wider purposes. It is in this environment that discrepencies in fundamental assumputions will become increasingly exposed.
The reason we don't speak of "physical variation" is that the physicist has chosen not to work with naturally occurring systems, but, rather, with the products of her laboratory. Most of her time in that laboratory is spent eliminating the variation and keeping it eliminated. Moreover, she must artificially ensure the survival of each aggregate, for a lump of pure gold, and especially a solution of pure glucose, would not survive long without the active participation of the scientist.
The reductionist - interested in "law" - emphasizes the sameness; the antireductionist - interested in "life" - emphasizes the difference. If the reductionist goes to the extreme, his laws are about systems that have zero probability of being observed; while if the antireductionist goes to his extreme, his systems also have zero probability of being observed - for if a system is truly unique, our minds cannot deal with it at all. In the first case the system does not exist, while in the second we have no way of observing its existence.