You might see the space in front of any objects you're looking at
The instruction to look at the space in front of objects instead at the (meditation) object has three purposes.
To de-focus, and thereby to de-personalise the meditator's view
To reduce the possibility to conceptualse and to particularise the objects
To facilitate becoming aware of the "inner space" of awareness
Note: I have no idea whether what I said is Sam Harris´s true intention. But these are possible ways to explain his pointing out instruction.
1. Defocused viewing
Defocusing reduces the felt sense of "Self". Since it is actually not possible to "focus on the space" (just try!), the effect is a more peripheral way of looking.
This is in contrast to focused looking, which can only be done using attention (as opposed to broad awareness). And, as John Churchill (2022) sais, attention is the lense of our Self.
To understand the difference between attention and awareness, read this post.
2. Less conceptualisation and particularisation
At the same time, looking at the space instead of the objects takes the attention of the objects and thereby reduces the tendency to "particularise" (ie to select specific objects from the broad field of awareness) and to "conceptualise" (ie to perceive at a higher level - e.g. to see "a chair" instead of a field of color and shape etc).
3. Physical space as pointer to inner awareness space
"Space" is one of the few traditional metaphors that Sam Harris uses for what he usually calls condition. This is the awareness spac in which all experience occurs.
In the above instruction, he uses the term "space" to shape the way of looking at the outer world. In related meditations, he instructs to look at the air. It it the same. In both cases, space and air also stand for the inner space, the vast expanse. So, if one practices to look at the outer space or air, one also practices to perceive the inner awareness "space".
Churchill, J. (2022, 12. Dezember). The Modern Hippie Podcast - EP17: Buddhist Contemplative Psychology & Metacognitive Awareness w/ Dr. John Churchill. Google Podcasts. Abgerufen am 6. März 2023, von https://podcasts.google.com/feed/aHR0cHM6Ly9hbmNob3IuZm0vcy85NTQzNWUyOC9wb2RjYXN0L3Jzcw/episode/M2FmZDNlMTgtMjgxMC00ZTMxLTg4Y2QtOGQ3MjFhMTNlMWU5?sa=X&ved=0CAUQkfYCahgKEwi4w8Gllsf9AhUAAAAAHQAAAAAQngQ
John Churchill used to learn with Daniel P Brown
Gebel, T. (2022c). Space and no boundaries and edges. Till Gebel. Retrieved March 6, 2023, from https://www.till-gebel.com/post/sam-harris-daily-meditation-2022-09-29-space-limitless-no-boundary-no-edge