The most common and most likely answer to this crossword clue is the 8 letter word IMMANENT
I
M
M
A
N
E
N
T
More clues leading to the result IMMANENT
Buddy explains!

The straight part
We know that "Natural" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case natural = immanent.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does IMMANENT mean?
IMMANENT adjective- Naturally part of something; existing throughout and within something; intrinsic.
- Restricted entirely to the mind or a given domain; internal; subjective.
- (of a deity) Existing within and throughout the mind and the world; dwelling within and throughout all things, all time, etc. Compare transcendent.
- (of a mental act) Taking place entirely within the mind of the subject and having no effect outside of it. Compare emanant, transeunt.
- Being within the limits of experience or knowledge.