"If + ing" possible?

Hi, KDog—Only if the -ing form functions as a substantive (or as a modifier of a noun) can "if" be followed by an -ing form.

• Only if owning guns is made illegal will people cease to buy them.
• Only if sitting ducks are visible will people be able to shoot them.

You are right that (c) works, but (d) does not. However, you can say: "Only by investing more money can we save the company."

@David, Moderator posted:

Only if the -ing form functions as a substantive (or as a modifier of a noun) can "if" be followed by an -ing form.

• Only if owning guns is made illegal will people cease to buy them.
• Only if sitting ducks are visible will people be able to shoot them.

You are right that (c) works, but (d) does not. However, you can say: "Only by investing more money can we save the company."

Hi, KDog and David,

I've been thinking this over and my impression is that, while it is certainly true that (d) does not work, there might be a case where an -ing form can be used as a reduced adverbial clause in front position (causing inversion), and this is when the verb in the -if clause expresses an existing state or a prior action (sometimes reinforced by already). Instead, when a by+-ing clause can be used to express the means by which or the manner in which the result in the main clause is to be achieved (as is the case with (d)), only if+-ing will not work.

- Only if living in an emerging country can you apply for that scholarship. (We cannot say: Only by living...)

- Only if coming from an English-speaking country will you be accepted as an interpreter in that congress. (We cannot say: Only by coming...)

Excellent point, Gustavo. I suspected that lurking in my grammatical blindspot was some type of acceptable reduced-adverbial-clause -ing construction following "if." You have found it and have described its semantics very well.