Are these two constructions semantically the same or different?



It is very common to use a to-infinitive or gerund clause at the beginning of a sentence as for the following:

  1. To drive a motorbike is dangerous.

  2. Driving a motorbike is dangerous.

My question is: Are they semantically the same or different?

Mido Mido

Posted 2017-12-05T09:44:24.280

Reputation: 720



The latter is fine because a gerund can serve as a subject in an English clause.

The former, however, is a bit awkward and unusual but still technically grammatical. An infinitive clause does not normally function as a subject but it's bound to be 'extraposed'. To do this, you move the infinitive clause to the end of the sentence and use the dummy pronoun "it" to fill the empty slot in the subject position.

i. [To drive a motorbike] is dangerous.
ii. __is dangerous [to drive a motorbike].
iii. It is dangerous to drive a motorbike.


Posted 2017-12-05T09:44:24.280

Reputation: 7 435

You're right. Moving the to-infinitive clause to a final position is better, but to-infinitive clause constructions in an initial position are sometimes seen as examples in grammar reference books. So my original question was about the difference in meaning between the to-infinitive and gerund clause constructions. – Mido Mido – 2017-12-12T15:19:09.393


The sentences are semantically and grammatically different.

Making errors is human.

To make errors is a verb and a complement but not the start of any sentence I can think of. I suggest making a sentence that begins with "to make errors " as the subject, and see if it would be any different, the same, or if it even made any sense.

  1. Making errors is human.

  2. To make error is human.

Not only the meanings of these two sentences are diverging, but they are also contradictory, in my opinion.


Posted 2017-12-05T09:44:24.280

Reputation: 5

Infinitives like "to drive" can act as subjects of verbs, so the sentence "to drive a motorbike is dangerous" IS a complete sentence. In (American) standard English, the gerund is commonly used as a subject, while the infinitive is not commonly used. It is unusual to use an infinitive this way, but it is still grammatical.

– fjack – 2017-12-08T04:04:30.247

BY + verb + ING – Specialist – 2017-12-08T05:33:23.627

1First, there is no passive form of the sentences "to drive a motorbike is dangerous" OR "driving a motorbike is dangerous" because the verb BE is not a transitive verb. Only verbs that take direct object can be used in the passive voice. – fjack – 2017-12-08T15:07:26.707

Second, while it is certainly true that prepositions such as BY can only be followed by the gerund form of a verb, that does not mean that other non-finite forms, such as the to-infinitive, cannot function as noun phrases in other constructions. Just because a construction (such as using the to-infinitive as the subject of a finite verb) is rare does not mean it is ungrammatical. – fjack – 2017-12-08T15:13:15.550

1To err is human. – Davo – 2017-12-12T14:46:08.743

To err is a verb. Making errors makes us human. – Specialist – 2018-01-22T08:35:50.633

1the noun "error" is countable. You can make "an" error, or you can make (several) "errors". – Mari-Lou A – 2018-01-22T16:17:16.103

Could you explain more how #1 differs from #2? Also, the sentence doesn't make sense. – user178049 – 2018-01-22T23:25:29.200

I also don't see how you conclude that the meanings are different. – Colin Fine – 2018-12-15T22:57:20.150