- The philosopher John Searle pointed out
that you can think of artificial intelligence
in two different ways.
There's strong AI, and weak AI.
Strong AI is when you have a machine
that displays all the behavior
that you'd expect from a full fledged artificial person.
This is usually what you see in science fiction movies.
These are artificial beings that have emotions,
a sense of purpose and can even tell jokes.
Some computer scientists also refer to strong AI
as general artificial intelligence.
General AI is a broad intelligence
that doesn't just apply to one narrow task.
Think of it this way, a strong AI machine
might learn a new language just for the joy
of learning a new language.
On the flip side, there's weak AI,
often called narrow AI.
This is AI that is confined to a very narrow task.
It might be like trying to process
your natural language into text.
Maybe it's trying to sort
all the pictures on your computer.
A weak AI program is not trying
to chat with you about the world.
It's just trying to assist you
with a very narrow task.
Most AI experts believe that
we're just starting down the path of weak AI.
That means that there are many organizations
already out there that are using weak AI
to help with these narrow tasks.
Thing about some of the newest AI assistants,
like Apple's Siri.
Each one is a good example of weak AI.
You can talk to them and even ask them questions.
Then they'll convert your language
into something that a computer will recognize.
They'll also do pattern matching
to connect your request to what's in their database,
but if you think about it, that's not that much different
from when you type something into Google or Bing.
The difference is that it seems
to behave much more like a human.
These artificial personal assistants will search the web,
your smartphone, and even your contacts and calendar.
They might even give you the same answer
that you'd get from a human assistant.
You can ask them to schedule your lunch,
or even call your friend.
It sticks to these narrow tasks
and follows your voice commands.
These personal assistants don't have
general artificial intelligence.
If they did, they'd certainly get tired
of listening to your requests all day.
Instead, they focus on a narrow task
of listening to your input,
and matching it to their database.
Most of the energy in AI is around developing
and expanding narrow AI.
As of right now strong or general AI
is still just the subject of science fiction.
John Searle was also quick to point out
that any software that uses the symbolic systems approach,
should be considered weak AI.
Remember that the symbolic systems approach
matches symbols in a way that seems intelligent.
Think of the person in the Chinese room.
They don't understand the language
but can match two different patterns of Chinese characters.
In the 1970's and 80's, symbolic systems
was used to create artificial intelligence software
that could make expert decisions.
These were commonly called expert systems.
In an expert system, you have experts create a list
of different steps that you could take
to make some conclusion.
If the long enough then it starts to feel like AI.
These expert systems were sometimes
used in the medical field.
A nurse might input a bunch of symptoms into a computer.
If the patient has a cough,
then checked if they have a temperature.
If they have a cough and a temperature,
then check if they're dehydrated.
If they have a cough, a temperature, and are dehydrated,
then it asks the nurse to check for Bronchitis.
To a patient, it might look like they're being diagnosed
by an intelligent computer.
In reality the program is just going through a long list,
just like they would in any medical textbook.
It's matching the symbols and patterns
that the expert created, to reach a possible diagnosis.
In the end, expert systems run into the same problems
as any other symbolic system approach.
They would lead to combinatorial explosions.
There were simply too many symbols
and too many matching patterns.
There's too much information serving as input.
Think about all the different questions
a good doctor might ask to reach an accurate diagnosis.
Yet the symbolic system was a key starting point
for artificial intelligence.
It's still used to this day
and in fact many experts still refer to it as GOFAI,
or good old fashioned AI.