The motions of our body, and the thoughts and sentiments of our mind, (say they) obey the will; nor do we seek any farther to acquire a just notion of force or power.

But to convince us how fallacious this reasoning is, we need only consider, that the will being here considered as a cause, has no more a discoverable connexion with its effects, than any material cause has with its proper effect.

So far from perceiving the connexion betwixt an act of volition, and a motion of the body; it is allowed that no effect is more inexplicable from the powers and essence of thought and matter.

Nor is the empire of the will over our mind more intelligible.

The effect is there distinguishable and separable from the cause, and coued not be foreseen without the experience of their constant conjunction.