Consciousness: here, there and everywhere? | Philosophical Transactions of the Royal Society B: Biological Sciences
A corollary of IIT that violates common intuitions is that even circuits as simple as a ‘photodiode’ made up of a sensor and a memory element can have a modicum of experience  (see also figure 5a, right panel). It is nearly impossible to imagine what it would ‘feel like’ to be such a circuit, for which the only phenomenal distinction would be between ‘this rather than not this’ (unlike a photodiode, when we are conscious of ‘light’ or of ‘dark,’ our experience is what it is because it includes scores of negative concepts, such as no colours, no shapes, no thoughts and so on, that are all available to us). But consider that normal matter at −272.15°C, one degree above absolute zero, still contains some heat. However, in practice its temperature is as cold as it gets. Similarly, there may well be a practical threshold for Φmax below which people do not report feeling much of anything, but this does not mean that consciousness has reached its absolute minimum, zero. Indeed, when we fall into a deep, dreamless sleep and don't report any experience upon being awoken, some small complex of neurons within our sleeping brain will likely have a Φmax value greater than zero, yet that may not amount to much compared to that of our rich, everyday experience.