  Objectivity, therefore, is essentially a characteristic of what is known. Certainty, in Rosmini’s view, is a characteristic of the person who knows, and can be defined as ‘a firm and reasonable persuasion that conforms to the truth’ (NE, vol. 3, 1044). In other words, we can be certain only of knowledge, not of error, and this because, according to Rosmini, to know and to know the truth is the same thing. The person who does not know the truth, does not know. There is no doubt, of course, that it is possible to be persuaded, and firmly persuaded, of error. But rational persuasion of error arrived at through one’s own reasoning is not possible. In this case, either the premiss is wrong, or the argument is erroneous. On the other hand, the persuasion must be firm. Certainty is not achieved without energy directed into persuasion. Certainty requires that we know something to be true, to be what it is, that we are persuaded that it is what we know it to be, and that we have an adequate reason for our persuasion. And precisely because error attempts to alter the being of things, formal error will not be found rooted in the intellect nor in the senses nor in involuntary reflection. It begins with the will, the only human faculty capable of drawing the reason to invent what it does not see, or to deny what it sees. Under pressure from the will, reason will falsely affirm that being is not, or deny that being is.