But at the same time I demand as an equitable condition, that if my system be the only one, which can answer to all these terms, it may be receivd as entirely satisfactory and convincing.
And that it is the only one, is evident almost without any reasoning.
Beasts certainly never perceive any real connexion among objects.

It is therefore by experience they infer one from another.

They can never by any arguments form a general conclusion, that those objects, of which they have had no experience, resemble those of which they have.

It is therefore by means of custom alone, that experience operates upon them.
All this was sufficiently evident with respect to man.

But with respect to beasts there cannot be the least suspicion of mistake; which must be ownd to be a strong confirmation, or rather an invincible proof of my system.
Nothing shews more the force of habit in reconciling us to any phaenomenoun, than this, that men are not astonished at the operations of their own reason, at the same time, that they admire the instinct of animals, and find a difficulty in explaining it, merely because it cannot be reducd tothe very same principles.