F=ma

The force at which two bodies meet are directly equivalent to the product of the density and size of those bodies.

The force at which two minds meet could theoretically be formulated, with Newton's Law, as the size of the heart and the contents of the brain. Now given the right circumstances for such a meeting of the minds and hearts to occur, the impact could be very significant. This impact results in a change in the way the objects move from that point on.

Force that my 6'3" body exerts on the surface of the earth is called my weight.
That force is really a measure of the potential impact that I could have on the earth and it in turn on me. The size of such an impact is really dependent on the rate at which the two object's relative movement changes. I fall to the earth from 20 meters in the sky and hit a rock - then I will come to an instantaneous stop and I would probably be exterminated, but if the air turns to water I would have a very slow deceleration and probably swim off unscathed.

So actually measuring the impact that two people have on each other has many additional complications, but I believe that Newton still explains this phenomena.

We speak about a heart, but also about someone that has heart. Having heart often makes people larger than life. So if I would equate that with the true size of a person then the depth of thought should be the measure of their density. So as the product of the volume and density of an object is equal to its mass so the heartful and thoughtful person will ultimately have greater inertia and less likely to be changed off course in the event of a collision with another. Two masses move along and their straight paths cross at a moment in time. The measure of their effect upon each other is relative to the direction of each object, the mass of that object and the speed of movement at the point of impact, which in turn is dependent on the possible acceleration of both or either object and the gravitational pull between the two objects.

I believe, just as the Newton model predicts, that the impact that two persons have on each other is directly proportionate to their direction in which they are moving. This would be an explanation for the commonly observed phenomena of two very opposite persons having such a great impact upon each other. And just like a bullet that impregnates its victim so too the impact that causes marriage and consequent pain from two opposite moving masses meeting, changes both objects and sends them careening into a completely new direction or at the very least it would be new for one of the two.

Now if this new found union isn't carefully steered, another such an impact could easily occur that once again could change the direction and speed of the combined masses or even dislodge the previous union to form a new combined mass.

But from all of this hypothesis there is one thing sure, and that is, that none of the objects involved with such collisions will ever move or be the same there after. They will ultimately be forever changed.

So the change that occurs in the human frailty is often dependent on which object has more mass and speed at the time of the impact. The product of the one who has more mass and speed would have the greater influence on the other's change. But even a very small directional change could over many years result in a very big difference.