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Technologies of the extended mind: Implications for privacy of thought

by Peter Reiner, PhD

Dr. Reiner is Professor and co-founder of the National Core for Neuroethics, at the University of British Columbia. Dr. Reiner began his academic career studying the cellular and molecular physiology of the brain, and in 1998, Dr. Reiner became President and CEO of Active Pass Pharmaceuticals, a drug discovery company that he founded to tackle the scourge of Alzheimer’s disease. Upon returning to academic life in 2004, Dr. Reiner refocused his scholarly work in the area of neuroethics. He is also an AJOB Neuroscience board member.

Louis Brandeis in his law office, 1890.
In 1890, Samuel Warren and his law partner Louis Brandeis 
published what has become one of the most influential essays in the history of US law. Entitled The Right to Privacy [1], the article is notable for outlining the legal principles that protect privacy of thought. But it is not just their suggestions about privacy that are illuminating – it is their insight into the ways that law has changed over historical time scales that makes the paper such a classic. In very early times, they write, “the law gave a remedy only for physical interference with life and property…[and] liberty meant freedom from actual restraint.” Over time, as society began to recognize the value of the inner life of individuals, the right to life came to mean the right to enjoy life; protection of corporeal property expanded to include the products of the mind, such as literature and art, trademarks and copyrights. In a passage that resonates remarkably well with the modern experience, they point out that the time was nigh for the law to respond to changes in technology.

Recent inventions and business methods call attention to the next step which must be taken for the protection of the person, and for securing to the individual …the right “to be let alone”. Instantaneous photographs and newspaper enterprise have invaded the sacred precincts of private and domestic life; and numerous mechanical devices threaten to make good the prediction that “what is whispered in the closet shall be proclaimed from the house-tops.”

The notion that privacy is problematic in a world dominated by instant communication is hardly new: as long ago as 1999, Sun Microsystems CEO Scott McNeally famously stated “You have zero privacy anyway. Get over it.”[2] This early sentiment on the invasiveness of technology has been borne out in chilling fashion with revelations that governments and corporations extensively monitor internet and cell phone use. It seems to me that the time is right to consider the proposition that continued changes in technology – in particular with respect to the life of the mind – require that we revisit the contours of the issue known as privacy of thought.

An important starting point is the extended mind hypothesis[3], the idea that cognition extends beyond the brain into the world at large. One example from the original paper – the case of Otto and Inga – illustrates the issue quite nicely. Inga hears about an exhibition at a museum that she recalls is on 53rd Street and sets off to see the artwork. Her neighbor Otto has dementia and so has made a practice of storing important information in a small notebook that he carries with him. When he hears of the exhibition, he consults his notebook, finds that the museum is on 53rd Street and, just like Inga, sets off for the same destination. Thus the cognitive function of storing information is mediated by the brain in one case and pen and paper in the other.

The claims of the extended mind hypothesis are radical: going beyond suggesting that human cognition relies on external structures for scaffolding and support, the extended mind thesis suggests that the physical vehicles that realize (at least some of) our cognitive processes lie outside of the bounds of the skull. Yet the concept resonates with a key feature of modern life: for many, there is a growing sense that computers, smartphones, and increasingly ‘the internet of things’ function as sophisticated extensions of our cognitive toolkit[4]. Conceiving of the mind as a blend between brain and algorithm challenges long-held assertions that there is something exceptional about the brain[5], but one ignores reality at one’s peril. Of late, I have begun to refer to the entire suite of algorithmic agents as “Technologies of the Extended Mind.”

If we return to the question of privacy and situate the discussion in the context of a worldview that considers “Technologies of the Extended Mind” as a growing reality, we see that there is some new and interesting terrain to explore. It is well-known that both breaches and oversharing of our digital information has grown from the occasional to an everyday event. But if “Technologies of the Extended Mind” really are extensions of our cognitive toolkits, at some point the ability of others (governments, corporations, employers, friends, hackers, and more) to glimpse this information crosses the line from being a run-of-the-mill invasion of privacy to a more worrisome intrusion upon privacy of thought. Defining this dividing line – even if it turns out to be a fuzzy boundary – is an important challenge for neuroethical discourse.

The fundamental insight of Warren and Brandeis – that changes in technology require us to at least revisit if not update our moral norms – is as relevant today as it was 125 years ago.


1. Warren, S. D. & Brandeis, L. D. The Right to Privacy. Harvard Law Review 4, 193 (1890).
2. Sprenger, P. Sun on Privacy: “Get Over It.” Wired News (1999).
3. Clark, A. & Chalmers, D. The extended mind. Analysis 58, 7-19 (1998).
4. Pew Research Center. Digital Life in 2025. 1-61 (2014) at 

5. Reiner, P. B. The rise of neuroessentialism. in: Oxford Handbook of Neuroethics (eds. Illes, J. & Sahakian, B. J.) 161-175 (Oxford University Press, 2011).


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