What does it say about the reality of the outside world if we can be fooled even about the state and composition of parts of our own bodies? And what does it say about the reality of our sense of self if we can’t trust our senses even when they report our apparent body states?
More evidence that the world, including us, is a construct, a mental representation of an otherwise un-experienced world “out there,” crops up in reports of a new study that fools subjects into believing that they have a phantom limb.
What makes this deception particularly remarkable is that the study’s subjects were not amputees. Whole-bodied subjects were tricked into ignoring their real limbs and interacting with their non-existent non-existent limbs. That’s quite a double negative!
In “Scientists Create Phantom Limbs in Non-Amputees,” reported on April 11th by Science Daily, researchers first hid each subject’s real right arm behind a screen. Testers then stimulated the hidden hand with a feather brush, while repeating the same action in the visible “blank space” where a phantom hand would have been. After only a short time, subjects “substituted” the non-existent non-existent hands for their hidden real hands, experiencing phantom phantom-limb sensations. When subjects closed their eyes and were asked to p0int their left hands at their right arms, while the illusion was in force they consistently pointed at the empty air where a phantom right arm would have been.
It’s one thing for an amputee to experience phantom pain. The simplest explanation is that nerves in the stump continue to send signals that used to come from the severed limb. But how to explain this result?
One explanation that makes sense is that we don’t experience the actual sensations that come from the nerves attached to our limbs. Rather, we use those sensations to construct a mental picture of the state of our bodies. And when the incoming sensations are visual tricks, our brains construct false pictures.
It’s long been argued by some that we live entirely inside our heads, that we have absolutely no direct connection to the outside world. Not only do we live with constructs, other research shows that the representations we create are situated in the very near past. How else, for example, would we experience someone’s talking and moving her lips at the same time, when light travels about 881,000 times faster than sound?
The notion that what we experience as reality, even the reality of our own bodies, is nothing much more than a time-delayed mental map is a major challenge for those scientists and philosophers who argue that our consciousness is “embedded,” a part of the material, outside world.
After all, if we can experience false sensations in falsely-false body parts, how tied are we to anything we can really call “reality”?