shall find that the phaenomenon is otherwise to be
accounted for. The suddenness and strangeness of an appearance naturally
excite a commotion in the mind, like every thing for which we are not
prepared, and to which we are not accustomed. This commotion, again,
naturally produces a curiosity or inquisitiveness, which being very
violent, from the strong and sudden impulse of the object, becomes
uneasy, and resembles in its fluctuation and uncertainty, the sensation
of fear or the mixed passions of grief and joy. This image of
fear naturally converts into the thing itself, and gives us a real
apprehension of evil, as the mind always forms its judgments more from
its present disposition than from the nature of its objects.

Thus all kinds of uncertainty have a strong connexion with fear, even
though they do not cause any opposition of passions by the opposite
views and considerations they present to us. A person, who has left his
friend in any malady, will feel more anxiety upon his account, than if
he were present, though perhaps he is not only incapable of giving him
assistance, but likewise of judging of the event of his sickness. In
this case, though the principal object of the passion, viz, the life or
death of his friend, be to him equally uncertain when present as when
absent; yet there are a thousand little circumstances of his friend's
situation and condition, the knowledge of which fixes the idea, and
prevents that fluctuation and uncertainty so near allyed to fear.
Uncertainty is, indeed, in one respect as near allyed to hope as to
fear, since it makes an essential part in the composition of the former
passion; but the reason, why it inclines not to that side, is, that
uncertainty alone is uneasy, and has a reladon of impressions to the
uneasy passions.

It is thus our uncertainty concerning any minute circumstance relating
to a person encreases our apprehensions of his death or misfortune.
Horace has remarked this phaenomenon.

UT ASSIDENS IMPLUMI BUS PULLUS AVIS SERPENTIUM ALLAPSUS TIRNET, MAGIS
RELICTIS; NON, UT ADSIT, AUXILI LATURA PLUS PRESENTIBUS.

[As a bird, watching over her fledgelings, is more afraid of their being
attacked by snakes if she were to leave them even though, were she to
stay, she would not be any more capable of helping them, when they were
with her.]

But this principle of the connexion of fear with uncertainty I carry
farther, and observe that any doubt produces that passion,