If spacetime is not fundamental, then our perception of visual space, and of objects in that space, is not a high-fidelity reconstruction of fundamental reality. What, then, is it? From the theory of evolution we can conclude that our sensory systems have been shaped by natural selection to inform us about the fitness contingencies relevant to us in our niche. We have assumed that this meant that our senses inform us of fitness-relevant aspects of fundamental reality. Apparently, they do not. They simply inform us about fitness, not fundamental reality.
In this case, the holographic principle points to a different conception of our perception of visual space. It is not a reconstruction of an objective, and fundamental, physical space. It is simply a communication channel for messages about fitness, and should be understood in terms of concepts that are standard for any communication channel, concepts such as data compression and error correction. If our visual space is simply the format of an error-correcting code for fitness, this would explain its holographic nature. Error correcting codes introduce redundancy to permit correction of errors. If I wish to send you a bit that is either 0 or 1, but there is a chance that noise might flip a 0 to a 1 or vice versa, then we might agree that I will send you that bit three times, rather than just once. This is a simple Hamming code. If you receive a 000 or a 111, you will interpret this, respectively, as 0 and 1. If you receive a 110 or 001, you will interpret this, respectively, as 1 and 0, correcting an error in transmission. In this case we use a redundant, three-dimensional format to convey a lower-dimensional signal. The holographic redundancy in our perception of visual space might be a clue that this space, likewise, is simply an error-correcting code—for fitness.
What about physical space? Research by Fernando Pastawski, Beni Yoshida, Daniel Harlow, John Preskill, and others indicates that spacetime itself is an error-correcting code—a holographic, quantum, secret-sharing code. Why this should be so is, for now, unclear, and tantalizing.