Toward a brain in a vat

To build a widespread, networked VR society, it is tempting to consider invasive BMI possibilities in a distant future. Before proceeding, recall the discussion of ethical standards from Section 12.4 and consider whether such a future is preferable. Suppose that in addition to measuring neural outputs, direct neural stimulation were also used. This would forgo the need to place displays in front of senses. For the eye, signals could be sent directly to the photoreceptors. This technology is called retinal implants, and already exists for the purpose of helping the blind to see. Similarly, cochlear implants help the deaf to hear. Neuroscientists, such as David Eagleman from Stanford, have even proposed that we could learn to develop completely new senses. An example is perceiving infrared or radio signals by remapping their frequencies, amplitudes, and spatial arrangements to other collections of receptors on the body, such as the back. The limits of neuroplasticity have yet to be fully understood in this way.

Rather than stimulating receptors, the engineered stimulus could even be placed at higher neural levels. For example, why bother with stimulating photoreceptors if the optic nerve could be directly stimulated? This would involve mimicking the processing performed by the ganglion cells, which is challenging, but would also reduce the bandwidth requirements in comparison to stimulating the rods and cones. Ultimately, direct neural measurement and stimulation could lead to the brain in a vat, which was mentioned in Section 1.1.

How do you know you are not already a brain in a vat, and an evil scientist has been taunting you while you read this VR book?