For decades, scientists have dreamed of building computer systems that could replicate the human brain’s talent for learning new tasks.
MIT researchers have now taken a major step toward that goal by designing a computer chip that mimics how the brain’s neurons adapt in response to new information. This phenomenon, known as plasticity, is believed to underlie many brain functions, including learning and memory.
Is free will an illusion? Some leading scientists think so. For instance, in 2002 the psychologist Daniel Wegner wrote, “It seems we are agents. It seems we cause what we do… It is sobering and ultimately accurate to call all this an illusion.” More recently, the neuroscientist Patrick Haggard declared, “We certainly don’t have free will. Not in the sense we think.” And in June, the neuroscientist Sam Harris claimed, “You seem to be an agent acting of your own free will. The problem, however, is that this point of view cannot be reconciled with what we know about the human brain.”
"Godfrey-Smith decided to connect this biological concept with his interest in the philosophy of mind, particularly in nonhumans. In 2010, he began a project with Alexandra Schnell, a graduate student at Macquarie University in Sydney, to conduct behavioral observation studies that address whether octopus intelligence differs from that of other species. Do octopuses learn differently? Does the decentralization of neurons mean cephalopods have multiple minds or competing consciousnesses?"
So Kripke's Modal Argument and Chalmers' Zombie Argument both rely on the notion of possible worlds that we touched on last week, and they're both arguments against physicalism, the idea that everything can be described in terms of physical properties - if it's not physical, fuck it. It's not real. That's an interesting thesis for philosophers of mind, because it sure seems like consciousness isn't just physical. Descartes famously imagined himself as nothing but a mind - if everything physical ceased to exist, he said he could definitely keep thinking.
 |
| Derek Parfit. Photo by Steven Pyke. |
Scientists use brain imaging to reveal the movies in our mind:
"Using functional Magnetic Resonance Imaging (fMRI) and computational models, UC Berkeley researchers have succeeded in decoding and reconstructing people’s dynamic visual experiences – in this case, watching Hollywood movie trailers. As yet, the technology can only reconstruct movie clips people have already viewed. However, the breakthrough paves the way for reproducing the movies inside our heads that no one else sees, such as dreams and memories, according to researchers."
Shepard & Metzler (1971) introduced the concept of mental rotation into cognitive science with what has become one of the best-known experiments in the field. This fame may, in part, be because the experiment is associated with a set of memorable graphical images (e.g., figure 1), some of which made it onto the cover of the issue of Science where it was first published. However, it is also a remarkably elegant experiment, that produced some strikingly clear results. The findings seemed directly to refute the Behaviorist doctrine, still holding considerable sway amongst psychologists at the time, that thought processes depend entirely upon language. By suggesting that analog representations have an important role to play in thinking, the findings also raised prima facie difficulties (though not necessarily insurmountable ones) for the (digital) computer model of the mind that lay at the heart of the newly emerging field of cognitive science (Block, 1983a).
Figure 1
Some of the stimulus figure pairs used by Shepard & Metzler (1971).
A- Identical objects differing by a rotation in the plane of the page
B – Identical objects differing by a rotation in depth
C – Mirror-image objects (also rotated in depth)
Shepard & Metzler presented their subjects with pairs of drawings of three-dimensional, asymmetrical assemblages of cubes, as shown in figure 1 A, B, and C. In each pair, the right-hand picture either showed an assemblage identical to that shown on the left, but rotated from the original position by a certain amount, or else it showed an assemblage that was not only rotated, but was also the mirror image of the one to the left (figure 1 C). The experimental task was to tell, as quickly as possible (by pressing a button) whether the two objects depicted were in fact identical (except for rotation), or were mirror images. Shepard's hypothesis was that the task would be done by forming a three-dimensional mental image of one of the depicted objects, and rotating this whole image, in the imagination, to see whether it could be brought into correspondence with the other picture. The experimental results clearly supported this idea, because it was found that, for each subject, the time taken to confirm that both objects of a pair were, in fact, identical, increased in direct proportion to the angular rotational difference between them. It was as if the subjects were rotating their mental image at a steady rate (although this might be different for each subject), so that the further they had to go to bring their image into correspondence with the reference picture, the longer it would take them. On post-experimental questioning, most of the subjects confirmed that this was indeed how they believed that they had done the task. (Interestingly, it made no difference whether the rotation was in the plane of the page, or in depth.)
 |
| William James |
As a final practical maxim, relative to these habits of the will, we may, then, offer something like this: Keep the faculty of effort alive in you by a little gratuitous exercise every day. That is, be systematically ascetic or heroic in little unnecessary points, do every day or two something for no other reason than that you would rather not do it, so that when the hour of dire need draws nigh, it may find you not unnerved and untrained to stand the test. Asceticism of this sort is like the insurance which a man pays on his house and goods. The tax does him no good at the time, and possibly may never bring him a return. But if the fire does come, his having paid it will be his salvation from ruin. So with the man who has daily inured himself to habits of concentrated attention, energetic volition, and self-denial in unnecessary things. He will stand like a tower when everything rocks around him, and when his softer fellow-mortals are winnowed like chaff in the blast.
The experiment helped to change John-Dylan Haynes's outlook on life. In 2007, Haynes, a neuroscientist at the Bernstein Center for Computational Neuroscience in Berlin, put people into a brain scanner in which a display screen flashed a succession of random letters. He told them to press a button with either their right or left index fingers whenever they felt the urge, and to remember the letter that was showing on the screen when they made the decision. The experiment used functional magnetic resonance imaging (fMRI) to reveal brain activity in real time as the volunteers chose to use their right or left hands. The results were quite a surprise.
"The first thought we had was 'we have to check if this is real'," says Haynes. "We came up with more sanity checks than I've ever seen in any other study before."
The conscious decision to push the button was made about a second before the actual act, but the team discovered that a pattern of brain activity seemed to predict that decision by as many as seven seconds. Long before the subjects were even aware of making a choice, it seems, their brains had already decided.
The Mind Uploading home page is dedicated to the putative future process of copying one's mind from the natural substrate of the brain into an artificial one, manufactured by humans. This technology will radically alter society in many ways, as science fiction authors have begun to illustrate. Through this server, explore the science behind the science fiction!See also, this article: "Uploading the Mind".
 |
| René Descartes |
Before I get into the experiment itself, here's the problem Searle is addressing - what does it mean for a machine to understand something? Is it possible we will ever produce a machine that can think on its own, that can learn and truly understand English? Offhand, it seems possible; after all, if we build a robot that speaks English as well as we do, who understands the nuances of language, who we just can't tell is a robot, then what exactly is the difference between his claim to know English and your best friend's claim to know English? This is the basis of the famous 'Turing Test' for AI - when we reach the point where we can no longer distinguish between a human and a computer when speaking to them, then we have truly achieved Artificial Intelligence.
