I will teach you the all. Listen closely.
What is the all? It is the eye and forms, the ear and sounds, the nose and scents, the tongue and tastes, the body and feelings, the mind and thinking. This is called the all.
Someone might say, "This all is not enough. I reject this all. I will proclaim another all. But because this is a groundless assertion, such a person, when asked about it, would not be able to show another all because that all is not within their sensorium. Such an assertion is merely a thought arising in the mind.
--- Samyutta Nikaya
This passage may be one of the earliest explications of the phenomenological experience of reality. It also describes the buddha's criteria for how and what we can know of reality: what is the source for knowing the nature of our experience? It is the totality of our sensorium (the six sense organs and the objects of the senses) because these six senses comprise the totality of our lived experience, our lived reality as opposed to our imagined, deluded story about reality.
Whatever the reality outside of the sensory apparatus, we can only know what we know through the sensory apparatus. The raw reality -- phenomena as they are -- cannot be known directly as our senses already condition what and how we can know and experience reality. It is in this way that we can say our sensory apparatus create our lived reality/experience.
For example: you and I have been presented the same meal. I take a bite and begin to gag and feel like I could vomit. You take a bite, savor the taste, sigh and smile with pleasure. Can we say that the taste of the food was the same or different? We can imagine similar scenarios for any of the senses: a scent I find delightfully pleasant may make you gag in revulsion, etc.
Remember, the buddha is much less interested -- if he is at all -- in metaphysical speculation than the alleviation of existential duhkha. His teaching of satipatthana directs us to pay full attention to the experience of the sensorium because that is where the duhkha arises and it will be the place where it ends. As Glenn Wallis writes, "...your experience is your reality. And your experience is your reality." Thus, if your experience is pervaded by duhkha, then paying attention to the nature of your experience is much more to the point than speculating about "reality."
This passage from the buddha also points to a fairly radical notion. The buddha is asserting that your sense organs and the data that comprise the totality of your experience is 'the all,' which is to say this all is your (lived) world! The buddha seems to be saying that those who posit another 'all,' such as a supernatural realm are misconstruing what is actually known. Those who speak of "knowing god" (or knowing "god") are not really clear on what it is that they actually know. According to this passage from the buddha, what they know are thoughts, concepts, perhaps visual imagery arising in their minds. Such mental formations are part of the sensorium and the only thing we can know. The error is the extrapolation from these mental formations to an entity that exists in the 'external' world. Recently, I read a Facebook thread where two devotees of new age thinking argued about what the "higher dimensional entities" they were in contact with thought about sexual relations for enlightened beings. One said they are beyond any such relationships while the other said they were so open as to be polygamous!
We all make all sorts of claims about the existence of things without taking the time and making the effort to look at just how we know them! The buddha is suggesting we get clear about just what it is that we know.