First, After we have performed any action; though we confess we were influenced by particular views and motives; it is difficult for us to persuade ourselves we were governed by necessity, and that it was utterly impossible for us to have acted otherwise; the idea of necessity seeming to imply something of force, and violence, and constraint, of which we are not sensible.

Few are capable of distinguishing betwixt the liberty of spontaniety, as it is called in the schools, and the liberty of indifference; betwixt that which is opposed to violence, and that which means a negation of necessity and causes.

The first is even the most common sense of the word; and as it is only that species of liberty, which it concerns us to preserve, our thoughts have been principally turned towards it, and have almost universally confounded it with the other.
Secondly, There is a false sensation or experience even of the liberty of indifference; which is regarded as an argument for its real existence.

The necessity of any action, whether of matter or of the mind, is not properly a quality in the agent, but in any thinking or intelligent being, who may consider the action, and consists in the determination of his thought to infer its existence from some preceding objects: As liberty or chance, on the other hand, is nothing but the want of that determination, and a certain looseness, which we feel in passing or not passing from the idea of one to that of the other.

Now we may observe, that though in reflecting on human actions we seldom feel such a looseness or indifference, yet it very commonly happens, that in performing the actions themselves we are sensible of something like it: And as all related or resembling objects are readily taken for each other, this has been employed as a demonstrative or even an intuitive proof of human liberty.