I often read the phrase "from simple to complex" and wonder if it is grammatically correct. The reason for the doubt is that "simple" and "complex" are adjectives and I am not sure if they can follow prepositions such as "from" and "to".


The Montessori principle of simple to complex says that when presenting an activity or a task to someone with Alzheimer's or dementia start simple and increase challenge gradually as the person becomes successful at the task. (https://tinyurl.com/y5h9axha)

"From Simple to Complex" (title of article: https://www.the-scientist.com/features/from-simple-to-complex-42874)

  • 'From' and 'to' can be used with quite a range of words, normally describing some sort of scale (one extreme to another for example). Consider 'from left to right' or 'from front to back'. Similarly to your example, 'from easy to hard' is also fine. So yes, 'from simple to complex' is correct.
    – JMB
    Feb 12, 2021 at 17:00

1 Answer 1


In your first example, the phrase is being used as a proper noun. It is the name of a specific principle and should probably be capitalized, quoted, or even hyphenated for legibility.

The Montessory principle of Simple to Complex says...

The Montessory principle of "simple to complex" says...

The Montessory principle of simple-to-complex says...

(As an aside, "The principle of simple to complex" is the full name.)

Your second example is a title. Titles often sacrifice correctness for style or conciseness because they have a limited number of words in which to convey the general meaning, subject, feel, or context of the body they title. Of Mice and Men springs to mind.

In general, from simple and to complex would not make sense on their own. However, the prepositional phrase from simple to complex describes a range.

One case where it may be useful is the following sentence.

I enjoy solving simple and complex puzzles.

This reads as if I enjoy solving two types of puzzles: simple ones and complex ones. Obviously, that is not what I mean to say. I enjoy solving all kinds of puzzles despite how simple or complex they may be.

I enjoy solving puzzles of simple-to-complex difficulty.

This expresses the fact that I enjoy solving a range of puzzles, but still misses that the range is not particularly important to me. It says that I enjoy solving puzzles in the range.

I enjoy solving puzzles of all difficulties, from simple to complex.

This expresses my meaning and is reasonably clear to a native speaker. The adjectives are in a non-standard location, but the sentence is still correct because the prepositional phrase is a range qualifying the difficultly of the puzzles I enjoy solving.

  • Thanks for the answer. I feel this last example feels correct because it has two unstated nouns. If I state them explicitly, it becomes "I enjoy solving puzzles of all difficulties, from simple [puzzles] to complex [puzzles]," which seems correct (but quite awkward). A related question is if we should say "from simple to more complex" instead. Or maybe "from the simple to the more complex"? What do you think? Feb 13, 2021 at 0:06
  • Yes, both of those are also good options and may be more clear to a general audience. I might even go with "from simple [ones] to the [ones that are] more complex."
    – D M
    Feb 13, 2021 at 0:24

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