All phenomena and events are necessary with only a relative necessity; for in depending upon causes, they all ultimately depend upon will. Considered therefore in themselves, they are contingent; for the will which produced them, either immediately or by second or dependent causes, is not necessitated, but free and contingent—and therefore their non-existence is supposable. But they are necessary relatively to will. The divine will, which gave birth to creation, is infinite; when therefore the nibus of this will was made, creation was the necessary result. The Deity is under no necessity of willing; but when he does will, the effect is said necessarily to follow—meaning by this, that the nibus of the divine will is essential power, and that there is no other power that can prevent its taking effect.
Created will is under no necessity of willing; but when it does will or make its nibus, effects necessarily follow, according to the connexion established by the will of Deity, between the nibus of created will and surrounding objects. Where a nibus of created will is made, and effects do not follow, it arises from the necessarily greater force of a resisting power, established by Deity likewise; so that whatever follows the nibus of created will, whether it be a phenomenon without, or the mere experience of a greater resisting force, it follows by a necessity relative to the divine will.
When we come to consider will in relation to its own volitions, we have no more necessity, either absolute er relative; we have contingency and absolute freedom.
Now certainty we have affirmed to relate to our knowledge or conviction of truths and events.
Necessity is one ground of certainty, both absolute and relative. We have a certain knowledge or conviction of that which we perceive to be necessary in its own nature, or of which a negative is not supposable; and this, as based upon an absolute necessity, may be called an absolute certainty.
The established connexion between causes and effects, is another ground of certainty. Causes are of two kinds; first causes, or causes per se, or contingent and free causes, or will; and second or physical causes, which are necessary with a relative necessity.
First causes are of two degrees, the infinite and the finite.
Now we are certain, that whatever God wills, will take place. This may likewise be called an absolute certainty, because the connexion between divine volitions and effects is absolutely necessary. It is not supposable that God should will in vain, for that would contradict his admitted infinity.
The connexion between the volitions of created will and effects, and the connexion between physical causes and effects, supposing each of course to be in its proper relations and circumstances, is a connexion of relative necessity; that is, relative to the divine will. Now the certainty of our knowledge or conviction that an event will take place, depending upon volition or upon a physical cause, is plainly different from the certain knowledge of a necessary truth, or the certain conviction that an event which infinite power wills, will take place. The will which established the connexion, may at any moment suspend or change the connexion. I believe that when I will to move my hand over this paper, it will move, supposing of course the continued healthiness of the limb; but it is possible for God so to alter the constitution of my being, that my will shall have no more connexion with my hands than it now has with the circulation of the blood. I believe also that if I throw this paper into the fire, it will burn; but it is possible for God so to alter the constitution of this paper or of fire, that the paper will not burn; and yet I have a certain belief that my hand will continue to obey volition, and that paper will burn in the fire. This certainly is not an absolute certainty, but a conditional certainty: events will thus continue to take place on condition the divine will does not change the condition of things. This conditional certainty is likewise called a physical certainty, because the events contemplated include besides the phenomena of consciousness, which are not so commonly noticed, the events or phenomena of the physical world, or nature.
But we must next look at will itself in relation to its volitions: Here all is contingency and freedom,—here is no necessity. Is there any ground of certain knowledge respecting future volitions?