According to Macquarie (Australia’s dictionary), the meanings are:
substantial: real or actual, of ample amount, of solid character, of real worth, having to do with substance, having to do with the essence of a thing.
substantive: having independent existence, belonging to the real or essential part of a thing, essential, real or actual, of considerable amount or quantity.
Obviously they’re very close in meaning. Sometimes Macquarie includes usage notes about words that might be easily confused, such as in the entry for ‘effect’, where the usage note says ‘not to be confused with affect’, but it does not for these two.
Searching a little broader (read: trawling the great google) was a little more useful. In fact, given the ease with which the internet erupts in apoplexy about infinitesimally subtle shades of meaning, it’s eerily quiet out there on this topic. (I have, however, learned from the interwebz that ‘Substantial’ is the name of a Maryland rapper. Yes, that’s him in the pic.) That tells me that either most people have a feel for it and get it right, or that most people don’t know the difference between them and so don’t know when they’ve been used incorrectly, or that the meanings are so close that to a large extent they are interchangeable. It seems from Macquarie (and from what you’ll see below) that it’s mostly this last reason.
Many lists aim to educate people about easily confused words, and these two do not appear on the most common ones:
- http://www.infoplease.com/ipa/A0200807.html. http://wordinfo.info/unit/4346/page:11
Even Grammar Girl didn’t have an entry about this.
But the formal sources do: Fowler’s Modern English Usage and the Australian English Style Guide (Peters).
Fowler’s has a couple of paragraphs on it: both words mean ‘of substance’, but they have become differentiated to the extent that ‘-ial’ is now the word in general use for real, of real importance, sizeable, solid, well-to-do, etc, and ‘-ive’, is chiefly used in special senses: in grammar, in parliamentary proceedings, in law, in the services. This is in the 2004 edition, by the way; the difference between ‘substantial’ and ‘substantive’ was not mentioned at all in the 1926 edition.
Peters also discusses this issue, saying that the two can appear in the same context but have a different focus. ‘Substantial’ is the more common of the two, by a factor of 14:1 and has more of a physical meaning, being about size or proportion. (This difference is usage would be explained by the narrower uses for ‘substantive’ given in Fowler’s above.) ‘Substantive’ is more abstract, and is to do with there being real issues. If a document is long and important in its content then it will be substantial and substantive; but a reader will prefer to get the substantive component without having to wade through substantial pages for it!
So ‘substantial’ has more to do with the amount of a change, and ‘substantive’ to do with affecting the substance itself. You might say that reducing a document by 20% through (for example, the paramedic method) was substantial but not substantive if the content was essentially the same, but that the document had undergone a substantive change if three new chapters were introduced while keeping the length the same by reducing the size of other chapters.
As to a memory device for this? I suggest the near rhymes of “a substantial meal is plentiful;a substantive argument is illustrative” could help. Now, put that into a rap.___________________________________________________________________________ Burchfield RW. 2000. Fowler’s Modern English Usage. Revised 3rd Edition. Oxford University Press. Oxford. Peters. P. 1995. The Cambridge Australian English Style Guide. Cambridge University Press. Cambridge. Image from: http://substantialmusic.wordpress.com/2012/07/03/music-free-download-sweet-dreams-1-spot-from-fanomm-chew-fu-x-substantial-x-j-cast/