account of causality
In considering Hume's account of the origin of the idea of 'necessary
connection' we have already collected most of the elements in Hume's
positive account of causality. In giving his positive account of
causality, Hume replaces necessary connection by the doctrine that events
of type A are constantly conjoined with events of type B. The conditions
that the cause must preceed the effect, and that causes and effects must
be contiguous in space and time are retained. So Hume's positive account
of causality is this.
We can legitimately say that A causes B if and only if:
- A preceeds B in time.
- A and B are contiguous in space and time.
- Events of type A are constantly conjoined with events of type B.
It is rather likely that as an account of the necessary and sufficient
conditions for causality Hume's account is not satisfactory. On the other
hand, as a psychological account of how we come to believe that A causes
B, it may do better. Given the way Hume talks, it may not be unreasonable
to take it in this way, rather than as a straightforeward definition of
causality. Having now grasped Hume's revolutionary account of
causality, we can now turn to his discovery of one of the great
problems in philosophy -- the problem of induction.
What Is The
Problem Of Induction?
Hume raises the problem of induction by noting that we have no problem
with matters of fact of which we are presently aware or which our memory
may tell us about. But this is a rather limitied sphere. What about
things of which we are not presently aware. Does Australia exist -- even
though I am not presently aware of any part of it? Surely it does, but
what justifies my confidence in this claim? Will copper conduct heat
tomorrow, or bread nourish me? Surely they will. But why am I justified
in holding that these things are true. As Hume puts it:
Pg. 323 "It may therefore be a subject worthy of curiosity, to enquire
what is the nature of that evidence which assures us of any real existence
and matter of fact, beyond the present testimony of our senses, or the
records of our memory."
Hume claims that all reasoning concerning matters of fact is based on
cause and effect. (Pg. 323) So, how do we know that cause and effect
claims about things of which we are not presently aware or assured of by
memory are in fact true? The answer is that we constantly suppose that
there is a relation between the present fact and that which is inferred
|Inferences from Present to Inferred
| Present fact:|| Inferred fact:|
| 1. a letter, or
knowledge of purposes||that his friend is in the
country or in France|
|2. finding a watch
or a machine in a desert|| that there had once been
men in that island|
|3. the hearing in the
dark of an articulate voice.|| the presence of some
person engaged in rational discourse.|
Cause/effect relations are discovered entirely by experience and not
a priori. (Pp. 324-5) Hume established this claim in his account
of causality which we have just finished exploring. The significance of
this point for the problem of justifying inductive inferences will emerge