tion makes all expectation as to the future irrational, even the expectation that we shall continue to
feel expectations. I do not mean merely that our expectations may be mistaken; that, in any case,
must be admitted. I mean that, taking even our firmest expectations, such as that the sun will rise
tomorrow, there is not a shadow of a reason for supposing them more likely to be verified than
not. With this proviso, I return to the meaning of "cause."
Those who disagree with Hume maintain that "cause" is a specific relation, which entails
invariable sequence, but is not entailed by it. To revert to the clocks of the Cartesians: two
perfectly accurate chronometers might strike the hours one after the other invariably, without
either being the cause of the other's striking. In general, those who take this view maintain that we
can sometimes perceive causal relations, though in most cases we are obliged to infer them, more
or less precariously, from constant conjunction. Let us see what arguments there are for and
against Hume on this point.
Hume summarizes his argument as follows:
"I am sensible, that of all the paradoxes, which I have had, or shall hereafter have occasion to
advance in the course of this treatise, the present one is the most violent, and that 'tis merely by
dint of solid proof and reasoning I can ever hope it will have admission, and overcome the
inveterate prejudices of mankind. Before we are reconcil'd to this doctrine, how often must we
repeat to ourselves, that the simple view of any two objects or actions, however related, can never
give us any idea of power, or of a connexion betwixt them: that this idea arises from a repetition
of their union: that the repetition neither discovers nor causes anything in the objects, but has an
influence only on the mind, by that customary transition it produces: that this customary transition
is, therefore, the same with the power and necessity, which are consequently felt by the soul, and
not perceiv'd externally in bodies?"
Hume is commonly accused of having too atomic a view of perception, but he allows that certain
relations can be perceived. "We ought not," he says, "to receive as reasoning any of the
observations we make concerning identity, and the relations of time and place; since in none of
them the mind can go beyond what is immediately present to the senses." Causation, he says, is
different in that it takes us beyond the impressions of our senses, and informs us of unperceived
existences.