Editor's Note: Paul Root Wolpe, Ph.D., is director of Emory University’s Center for Ethics.

By Paul Root Wolpe, Special to CNN

(CNN) - “My thoughts, they roam freely. Who can ever guess them?”

So goes an old German folk song. But imagine living in a world where someone can guess your thoughts, or even know them for certain. A world where science can reach into the deep recesses of your brain and pull out information that you thought was private and inaccessible.

Would that worry you?

If so, then start worrying. The age of mind reading is upon us.

Neuroscience is advancing so rapidly that, under certain conditions, scientists can use sophisticated brain imaging technology to scan your brain and determine whether you can read a particular language, what word you are thinking of, even what you are dreaming about while you are asleep.

The research is still new, and the kinds of information scientists can find through brain imaging are still simple. But the recent pace of progress in neuroscience has been startling and new studies are being published all the time.

In one experiment, researchers at Carnegie Mellon looked at images of people’s brains when they were thinking of some common objects – animals, body parts, tools, vegetables – and recorded which areas of their brains activated when they thought about each object.

The scientists studied patterns of brain activity while subjects thought about 58 such objects. Then they predicted what the person’s brain would look like if researchers gave them a brand new object, like “celery.”

The scientists’ predictions were surprisingly accurate.

Many scholars predicted as recently as a few years ago that we would never get this far. Now we have to ask: If we can tell what words you are thinking of, is it much longer before we will be able to read complex thoughts?

In another experiment, researchers at the Max Planck Institute of Psychiatry in Munich, Germany, sought out a group of “lucid dreamers” - people who remain aware that they are dreaming and even maintain some control over their dreams while they sleep.

The researchers asked the subjects to clench either their right hand or left hand in their dreams, then scanned their brain while they slept. The subjects’ motor cortex, the part of the brain that controls movement, lit up in the same manner it would if a person clenched their left hand while awake – even though the actual hand of the sleeping subjects never moved.

The images revealed that the subjects were dreaming of clenching their left fists.

Throughout human history, the inner workings of our minds were impenetrable, known only to us and, perhaps, to God. No one could see what you were thinking, or know what you were feeling, unless you chose to reveal it to them.

In fact, the idea of being able to decipher what is going on in that three pounds of grey mush between our ears seemed an impossible task even a couple of decades ago.

Now, for the first time in human history, we are peering into the labyrinth of the mind and pulling out information, perhaps even information you would rather we did not know.

Neuroscientists are actively developing technologies to create more effective lie detectors, to determine if people have been at a crime scene, or to predict who may be more likely to engage in violent crime.

As the accuracy and reliability of these experiments continue to improve, the temptation will be strong to use these techniques in counter-terrorism, in the courtroom, perhaps even at airports.

And if brain imaging for lie detection is shown to be reliable, intelligence agencies may want to use it to discover moles, employers may want to use it to screen employees, schools to uncover vandals or cheaters.

But should we allow it?

I believe not. The ability to read our thoughts threatens the last absolute bastion of privacy that we have. If my right to privacy means anything, it must mean the right to keep my innermost thoughts safe from the prying eyes of the state, the military or my employer.

My mind must remain mine alone, and my skull an inviolable zone of privacy.

Right now, our right to privacy – even the privacy of our bodies – ends when a judge issues a warrant. The court can order your house searched, your computer files exposed, and your diary read. It can also order you to submit to a blood test, take a drug screen, or to provide a DNA sample.

There is no reason, right now, that it could not also order a brain scan.

Right now, the technology is not reliable enough for the courts to order such tests. But the time is coming, and soon.

Eventually, courts will have to decide whether it is allowable to order a defendant to get a brain scan. There is even an interesting question of whether forcing me to reveal my inner thoughts through a brain scan might violate my Fifth Amendment protection against self-incrimination.

But not even a court order should be enough to violate your right to a private inner life. The musings of my mind and heart are the most precious and private possessions that I have, the one thing no one can take away from me.

Let them search my house, if they must, or take some blood, if that will help solve a case. But allowing the state to probe our minds ends even the illusion of individual liberty, and gives government power that is far too easy to abuse.

The opinions expressed in this commentary are solely those of Paul Root Wolpe.