Page 48 - Deep Learning

The Nature of the Enterprise 31

it is in the past. There is no other way for the past to act in the present than
through our representation of it. Similarly, a prediction is a representation of
something future, something that has not yet become actual. We sometimes
act in response to a prediction – if the forecast says rain, we pack an umbrella –
but the future could not possibly cause our decisions or actions, because it
does not yet exist and cause comes before effect. Like the past, the future can
only act in the present via our representation of it.
The power of cognition is greatly increased by our ability to form abstrac-
tions. Mathematical concepts like the square root of 2 and a four-dimensional
sphere are not things we stumble on during a mountain hike. They do not
exist except in our representations of them. The same is true of moral concepts
like justice and fairness, as well as many less moral ones like fraud and greed.
Without representation, we could not think with abstractions of any kind,
because there is no other way for abstract entities to be available for reflection
except via our representations of them. 18
The necessity of postulating representations is even more obvious when
we consider goals, desires and intentions. A goal is not a representation of
something that exists; if we have it in hand already, it is no longer a goal. A goal
is a representation of something that does not yet exist, so it is a subspecies of
representations of the future, but with a twist: Goals represent some desired
aspect of the future. The property of being desired is not a physical attribute.
It does not inhere in an object or a state of affairs but is assigned to it by some-
body, so it can exist only as part of the person’s representation of that object or
state of affairs.
Finally, representation enables imagination: We can fantasize about things
that have only a thin connection to reality. Counterfactual reasoning has been
developed to a fine art in what is known as alternate history (if Germany had
won the Battle of the North Atlantic, then …). We can even represent to our-
selves events, objects and states of affairs that we firmly believe to be impos-
sible. Santa Claus visiting every child in a single night is one example; time
travel – a staple of science fiction – is another. We do not believe that these
things are possible, but we can invent stories about them and so represent
them to ourselves as well as to each other. In short, our ability to mentally
manipulate the present, the past, the future, the abstract and the fantastical
highlight and prove the representational nature of mind.
Cognitive scientists frequently refer to the mind’s representations as
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knowledge representations. In doing so, they use the term “knowledge” in
a different way than philosophers. The latter have had a hard time with the
concept of knowledge. What does it mean for a statement to be true? What