When used in a strictly legal sense, the wording would be "intent and purposes," as it refers to one's mental attitude/state at the time said action occurred.
A common malapropism is "for all intense and purposes" (also, "for all intensive purposes") a result of the original phrase being misheard and repeated. The word "intense" is used here incorrectly; "intense" is used in English to indicate a degree of intensity, i.e., "As the afternoon passed, the fire grew more intense."
Suggestion
It is important to avoid malapropisms as far as possible, as some people take them as a hallmark of ignorance and lack of education. If you have problems with "to all intents and purposes," bear in mind that in that expression "intents" is redundant. Use one of the alternatives suggested above.
Neither of the phrases in the question is correct.
The correct wording, in American English, is "for all intents and purposes." In British English, however, the wording of the selfsame idiom is "to all intents and purposes."
The correct saying is "all intents and purposes".
It Differs between American and British English"For all intents and purposes" is the correct phrase according to American usage. The British version of the idiom is "To all intents and purposes."(See the Related link.)
"All" needs to modify a plural noun, so "intents and purposes" would be correct.
'to all extent and purposes' means that it is correct for every possible scenario, so from what ever angle you were to look at it it would be true.
Light, moderate, or soft may all be used as antonyms depending of the circumstances.
In England we have a saying "all's well that ends well",could this be what you are asking?
The correct idiom is the second one. You'd say "for" when saying "intents and purposes" because you're doing something for some reason. You don't do something to a reason.
It Differs between American and British English"For all intents and purposes" is the correct phrase according to American usage. The British version of the idiom is "To all intents and purposes."(See the Related link.)
"All" needs to modify a plural noun, so "intents and purposes" would be correct.
Outdoor Channel Outfitters - 2009 For All Intents and Purposes was released on: USA: 24 March 2011
For all intents and purposes, no.
For almost all purposes and intents, yes.
for all intents and purposes, the sun is the only solar energy there is.
To all intents and purposes - non existent.
For all intents and purposes, yes, in the Indianapolis area.
To all intents and purposes it was forced on them by the allies after the second world war
For all intents and purposes, North Korea is a totalitarian monarchy.
They are, for all intents and purposes, burial mounds. Granted, burial mounds for the extremely wealthy.