-------When we use a balance scale to measure weight [mg] we are making use of the quantity [g] that with respect to the balance scale function, is a consequence of the balance scale's location in space. The quantity [g] at the balance scale location acts uniformly on each pan of the balance scale and on the observer, and persists as a uniform attraction on the contents of each pan to bring the comparative resistance quantity mass [m] to balance in the attraction field that acts uniformly on atoms. The uniform quantity [g] at location allows the observer to measure comparative magnitudes of non- uniform atomic matter in conserved quantitative uniform units that the observer feels as resistance and defines as mass [m]. The balance scale compares the resistance of two pans of matter.
[mg]1 = [mg]2 on the balance scale where [g] divides out because it is a uniform external to the balance scale influence on each pan.
The balance scale compares at any location [g] the resistance [m] of the non-uniform pans of atomic matter. The observer feels the product [mg] at location [g]. The observer views the conserved comparative resistance [m] at any location, as a partial causal factor of the variable location product, weight [mg], that the observer feels. This is a sound conclusion.
The observer also concludes that the weight [mg] is equal and opposite to a force the observer applies and feels [F=mg]. This is not a sound conclusion. The quantity [mg] is a resistance that is equal to a force the observer applies [F=mg]. This is a sound conclusion.