Chicago, born 1942

Ned Block

Organise the whole population of China to act out the workings of a brain, and the system would be functionally like you. Would it feel anything? If not, functionalism has left something out, and that something is phenomenal consciousness.

The view

Block, a professor at New York University, studied with Putnam and took functionalism seriously enough to find its weakest point. In "Troubles with Functionalism" (1978) he argued that a system could have exactly the right functional organisation and yet have no experiences at all. Functionalism might capture thinking, but not feeling. Later, in "On a Confusion about a Function of Consciousness" (1995), he drew a distinction that has organised the science of consciousness ever since.

Access consciousness is information being available for reasoning, report and the control of action. Phenomenal consciousness is experience: what it is like. The two usually go together, but Block argued they are different things, and that many theories which claim to explain consciousness in fact explain only access.

The argument

Would a billion people with radios, acting out a brain, feel a pain? After Block, "Troubles with Functionalism" (1978)

Suppose the Chinese government agrees to implement a human mind for an hour. Each of a billion citizens is given a two-way radio and instructions for what signal to send when particular signals arrive, just as a neuron fires when its inputs reach threshold. The radios are linked to an artificial body. Functionally, the arrangement duplicates your brain, so it should, if functionalism is right, have your mental states. When the body is pricked with a pin, it winces and says "ouch". But is there anything it is like to be the nation of China? Block thought it absurd to suppose so.

The access and phenomenal distinction comes with an empirical argument. In George Sperling's 1960 experiments, people shown a grid of letters for a split second could report only a few, but could report any row they were cued to afterwards. Block argued that they consciously saw all the letters, phenomenally, but could access only some. Consciousness "overflows" what we can report. If he is right, there can be experience that no report reveals.

Where he meets Dennett

Both took the science seriously and argued from experiments as well as intuitions. Both accept that access consciousness, the availability of information for report and control, is real and is a matter of what the brain does. Block's distinction is one Dennett used too, in order to say that once access is explained, nothing remains.

Where they part

On the China brain, Dennett's reply was the same as to the Chinese room. The intuition that the nation feels nothing comes from picturing something much simpler than a working brain: a few people with radios rather than billions of interactions at enormous speed, sustained over a lifetime. Imagined properly, the case gives no clear verdict. Size and slowness are not evidence of an absence of mind.

On overflow, the disagreement is direct, and it is the one Dennett mentions in his 2016 essay. In a paper with Michael Cohen and Nancy Kanwisher (2016), he argued that the apparent richness of experience beyond what we can report is itself an illusion. We have a rich sense of the scene's gist and statistics, and we take it for a detailed picture. On Dennett's view phenomenal consciousness without access is not a hidden extra that experiments might find. It is a confusion about what the experiments show.

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Further reading

• Ned Block, "Troubles with Functionalism", Minnesota Studies in the Philosophy of Science 9 (1978).
• Ned Block, "On a Confusion about a Function of Consciousness", Behavioral and Brain Sciences 18 (1995).
• Michael A. Cohen, Daniel C. Dennett and Nancy Kanwisher, "What is the Bandwidth of Perceptual Experience?", Trends in Cognitive Sciences 20 (2016).
• Ned Block, The Border between Seeing and Thinking (Oxford, 2023).