By (I) a sensory hallucination or (2) a massive sensation, both being of telepathic origin.
Prof. Josiah Royce has suggested for this supposed form of hallucination the term "pseudo-presentiment."
The contents of experience are not all alike true or valid: hallucination is possible; here the Stoics join issue with Epicurus.
She'd dared to hope again that everything was a hallucination brought on by too much alcohol, until Toby burst in chasing a cat she didn't remember owning.
From an evidential point of view the apparition is the most valuable class of death-warning, inasmuch as recognition is more difficult in the case of an auditory hallucination, even where it takes the form of spoken words; moreover, auditory hallucinations coinciding with deaths may be mere knocks, ringing of bells, &c.; tactile hallucinations are still more difficult of recognition; and the hallucinations of smell which are sometimes found as death-warnings rarely have anything to associate them specially with the dead person.