I have to agree, Newtons original verbal formulation as quoted on this page was expressed in the order of the more self evident cause and effect, a change in acceleration is proportional to (caused by) an applied external force not the other way around.
F=ma
does not actually capture the causal aspect of the law, and it's not what Newton is quoted as saying. F is instantaneous and causes a change - a change to momentum, which is a state, temporally extended. Probably it's a consequence of this that the modern sentence expressing Newtons second just reads this equation out loud, and doesn't mention causality at all.
1) We (as a culture) should probably fix that, I won't cause I'm not a professor.
2) Also Maybe something like
a(F)=F/m ... a is function of F
Would be a better equaton. This form has more characters on the down side, but it does avoid sacrificing the causal semantics.
Against Counter Args: Scenarios in which a change in momentum (perhaps due to climbing a hill) causes a change in applied force are more difficult to construct. Especially considering 1) a change is a difference in the same body at two instances in time, not a difference between two different bodies. 2) the instantaneous nature of force allows any changing force to be equally well described as a series of different forces
So there we are, the popular formulation of Newtons 2nd law "disproved". Next proof black is white (oh wait - Black Body radiation - its been done). Actually there are probably a lot of physical equations suffering from this kind of causal degredation.