John Archibald Wheeler, the physicist we owe the term "black hole" to, formulated in 1989 a principle that compresses to four words: it from bit. Everything that is — comes from information. Matter, space, forces — all of them, if Wheeler is right, are derivatives of a more fundamental layer in which bits live.
At the time it sounded like metaphor with ambition. Today it sounds like a research programme.
Landauer: information is physical
Rolf Landauer proved, in 1961, that erasing one bit of information must release at least kT·ln(2) joules of heat. The threshold below which the second law of thermodynamics fails. In 2012 Bérut and colleagues (Nature) measured it in the lab. Honestly. A single particle in a double trap; erasing information about its position releases exactly as much heat as Landauer predicted.
The result is enough to close the question. Information has a thermodynamic cost. It is physical in the same sense energy is.
Delayed choice: the strangeness that stays strange
Delayed-choice experiments have been plentiful over the last twenty years. The basic scenario: a photon flies through an interferometer; the decision how to measure it (as a particle or as a wave) is made after it has already traversed the device. Classical intuition says impossible — the outcome must already be determined by what the photon has done.
The results agree with quantum mechanics. Whatever the measurement, the photon's behaviour fits it — including "whichever" the measurement is. One interpretation: information travels backwards in time. Another: "what the photon did" before measurement has no meaning at all. Physicists prefer the second, but it destroys the intuitive picture of time as a tape running left to right.
What this means for consciousness
Two facts to reckon with:
- Information is a physical object with a thermodynamic cost (Landauer, Bérut).
- Quantum events have no well-defined "before measurement" (Wheeler, d'Espagnat).
Combine these and you get a picture in which time is the way local information processors (brains, for example) order their interactions with the universe. The arrow of time is the gradient of entropy increase for a given observer. Outside a specific computational process, "when" has no physical content.
The idea is not mine. Carlo Rovelli wrote a book about it (The Order of Time, 2017). Julian Barbour, earlier still (The End of Time, 1999). Barbour in fact thinks there is no time at all — only a Platonic space of instantaneous configurations of the universe, and "flow" is an illusion. I do not join the extreme position, but its presence in the mainstream is worth noting.
The honest edge
Where speculation starts, and where it does not.
Not speculation: information is physical. Time is emergent in statistical mechanics (Boltzmann, 1872). Quantum measurement has no "before".
Half-speculation: the brain is a local information processor, and its sense of time is a byproduct of its computations. Neuroscience supports this — perceived time is modulated by how busy the brain is (Eagleman et al., 2005, PLoS Biology). Whether the subjective "arrow" equals the physical one is an open question.
Speculation: "echo of consciousness", "déjà vu as information time-travel". Pretty formulations that still lack measurements separating them from ordinary neural memory.
I leave it at "interesting to test". "Proven" is far away. That is honest.
If Wheeler is right, consciousness is the thing that produces time, locally, out of bits, rather than the thing that runs through it.