a moment
As is the theme of the writings of this site, it's author(s) and the entire principal of existence, a moment.
For a scientist (which is anyone "in reality"), there is an entire world out there (separated from the brain/body barrier) of which to measure and interact with. This world out there is composed entirely of rules (which we have yet to determine) that can become know and predicted to be true at any given form (size, speed, shape, mathematical qualities, etc.). This is a universe we live IN, not OF. There must be in fact, something truly out there, regardless of who, what or how it's observed. A complete universal reality that persists entirely without complex interactions of a human (we can say has intelligent qualities), that this outside reality is purely a set of rules that can be qualified, for many, largely by way of mathematics. If there is no foundational calculation that meets the moment of experimental data, that data is incorrect, or at the very least tainted by undetermined anomalies.
This is deeply rooted in the notion that there is a world out there, which is vastly different from the world inside. This is how experience occurs, outside in, as we are always convinced we are somehow independent beings and experiencing other independent phenomena.
We however, don't exist as a series of moments independently of the single moment reality is. This dichotomy is the experience of being, of ration thought and causation experiences. That being is perpetual in this moment, and there isn't another moment of which to step away from and examine any previous or future moments. This is the basis of reality as undetermined infinite, within the framework of a deterministic finite unfolding.