Will the human brain ever be replaced by a computer?

With about 100 billion nerve cells, each of which is connected to another 10,000 or so neurons, the natural neural network inside our heads is a very complex thing. In particular, the ability to process many stimuli and signals in parallel is still underdeveloped in computers.

As of June 2016, the world's fastest supercomputer—Sunway TaihuLight—performs 93 quadrillion calculations per second—in computing jargon, these are called petaflops.  

It has been calculated that even a rough replication of the human brain would require a machine capable of at least 10 petaflops, this computer is over nine times faster than that.

However, the Sunway TaihuLight is a pretty sizable beast.

While it might be too big to fit into our craniums, it sure is helping to save our asses. It's hoped that it will be able to analyse some incredible data that may ensure we never run out of food and even 'manage' climate change, by tackling fundamental problems such as increasing the yield of crops to keep up with population growth. Pretty ambitious. 

Read more: How we learned to stop worrying about the microchip and love the computer

Just because we have something super-fast it doesn't make it super-best. Some things to consider when thinking of computers in a human light:

Although computers might be able to process information quicker than humans, the type of information they process and the way it's organised differs. It's important not to mistake the speed at which something is processed for intelligence.

This is a tricky one to define.

On the one hand, it does include the ability to acquire and apply knowledge, but outside of the dictionary definition it also includes things like analysis, questioning, skill and application—this might require some creative reasoning.

Analysis, decision making, and application are usually based on a set of criteria. Machines may be able to make quick decisions but these are always based on the criteria defined by a human programmer.

When it comes to decision making and applying knowledge, humans can lean on a set of values often acquired through experience. Machines often cannot compute the level of contradictions involved in processing values. 

Logic is really puzzling for artificial intelligence, especially where ethics are concerned. 

For example, you can give a robot a set of conditions that state "physical assault is a crime" but what makes a physical action a crime involves a little more information.

Take this statement for example: 

A husband turns to his wife and says "I'm leaving you," the wife responds "Who is she?". This statement is fairly straightforward to comprehend as a human but as a machine, it requires a few leaps that rely upon learned experience and values.

For computers to catch up and take the place of a human brain, they would have to learn one important thing: empathy. That is where humans and machine will always differ.

Philip K Dick's fantastic science-fiction novel Do Androids Dream of Electric Sheep? (later made into the film Blade Runner) asks an important question. Machines may one day be able to fake empathy by learning the way humans react to certain situations, but will they ever be able to actually acquire the ability to empathise with others?

Films like A.I. Artificial Intelligence and the Channel 4 series Humans delve into this conundrum with great emotive affect.

Read more: 13 Robot films to make you feel more human

If a computer is fed sufficient data, it can combine it in unexpected ways. At first glance, solutions to problems that have arisen in this way may indeed appear to be the result of creative processes. However, their origins still lie in the natural creativity of the programmers, not the machines. 

The human brain is complex and appears to be capable of more creativity. If a sufficiently complex computer becomes available will the differences between human and machine still be apparent? Or will we not be able to tell the difference? In the case of the latter, we may have some huge philosophical questions to answer—but perhaps a machine will be able to answer them for us.

Clip from the 2005 adaptation of The Hitchikers Guide to the Galaxy. A supercomputer is built to answer the biggest question: the meaning of life, the universe, and everything

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For work on artificial intelligence (AI) to be taken seriously, there had to be a way of proving that ‘intelligence’ was actually present. The Turing test was developed in 1950 by British mathematician Alan Turing and is still considered the most important hurdle for so-called intelligent machines to overcome.

Turing stipulated that a computer could be described as intelligent when a human judge, addressing an unknown source at the other end of an electronic link—a phone line or terminal—could not tell whether the source was human or machine.

During the annual contest for the Loebner Prize for Artificial Intelligence, which is based on the Turing test, the aim is for three out of 10 judges to be fooled for at least five minutes by the answers provided by a computer.

In 2014 the University of Reading claimed that a chatbot (a machine that is programmed to use and learn human speech based on interactions with human beings) fooled 33% of the human judges during text conversations.

However, many claim this was a publicity stunt to mark the anniversary of the test. For starters, it was not a supercomputer, it was an algorithm; a piece of software. The British judges were also told that the subject was a 13-year-old boy from the Ukraine, which may have explained away their suspicions when it came to bad grammar. 

No one has claimed to have beat the Turing Test since.

A robot is created with the typical human values and ambitions. It is programmed to learn from its encounters with humans and grow more intelligent. Is it a glitch in the system that causes her to say she wants to destroy humanity, or has she learned the negative side of humanity?

Read more: What does Google know about you?

While it might be quite some time before a computer takes over the entirety of the human brain (or before machine overthrows humanity mwahaha), technology is advanced enough to perform certain activities of the brain, and help those whose brains don't function effectively.

Brain implants are helping people with:

Obviously, there are some ethical considerations here. Usually, people are divided into two camps: transhumanist or bioconservative.

With such controversy, there are also legalities to consider. For example, the person with the implant must have volunteered themselves and not have been forced. As technology improves these laws will not only keep research humane but will inevitably grow to keep us human.

This piece was expanded and updated from 1001 Science Questions Answered, 2008, Reader's Digest. Contributors included: Dr Robert Coenraads, Dr Joachim Czichos, Cornelia Dick-Pfaff, Dr Rainer Kayser, Dr Kathy Kramer, Jan Oliver Löfken, Karen McGhee, Dr Doris Marszk, Dr John O’Byrne, Dörte Saße, Richard Whitaker, Marita Willemsen 

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