Which sentence is the most natural and grammatically correct :
From the time I was a child, I know something is wrong with me.
From the time I was a child, I have known something is wrong with me.
I would prefer the second one with the present perfect tense because it fits in the definition of the present perfect tense: The realization of the fact that somethings were wrong with me started in the past, and I still know somethings are wrong with me.
Concur. The given construction is grammatical with I knew.
“From the time I was a child” fixes the time of the action in the past with implication that it continued to later time but without requiring it to be continuing to the present.
If you wish it to be continuing action from past to the present, then it should be Since I was a child, I have known…
The first thing to keep in mind is that the “present perfect” is not perfective. It would better called the imperfect. This all stems from an idiotic attempt to impose Latin grammar on English. On a mistaken theory that Latin was the ideal language and all other languages had to be modeled on it.
The real facts about the English verb are: A verb has two inflected forms usually called the present and past. These are misnomers. The present should be called the imperfect and the past called the perfect. These terms are simplified, but are the best we have. The imperfect may be used for the present, but also for the future and past. “I go to my office every day” refers to present, past, and future time. The difference between “X has proved that…” and “X proved that…” is often that X has died and is no longer proving theorems. (Although this might seem like an odd example, I am a mathematician and found myself making exactly that change in my speech after a friend died.)
There are many ways of expressing future time and there is absolutely no reason to privilege the “will” forms. I’m not sure, but I think I use “going to” as often, maybe more often. In the OP, it is clearly complete action and so neither the “present” nor “present perfect” is appropriate, but the “simple past” form “knew” is. I think every poster said that. This illustrates that we all know these facts, we just haven’t stated them explicitly.
Those “grammarians” did a lot of damage to the proper study of English.
“From the time I was a child, I have known something is wrong with me” sounds OK to me (although I might say “something *was *wrong with me”).
To me, the following two sentences have slightly different meanings:
From the time I was a child, I knew something was wrong with me
*From the time I was a child, I have known something is *[or was] wrong with me
The first is taking about the period from childhood to some later time that is also in the past. It’s how one might express the idea in an autobiography, for example - looking back on one’s life as past events. The second is talking about the period from childhood up to now, and the action could be ongoing.
I can’t think of any time where the first construction would be appropriate, though. And you’re leaving out the construction “I had known,” which is the one that I think would be appropriate if you were talking about knowing up to a certain point in the past.
The opening phrase establishes that this a continual action, which to me feels like it cannot work with the simple tenses. Can you give me an example that would be correct?
(And, while Hari Saldon’s facts are correct, I disagree that the other way is easier. It’s easier having more tenses than fewer.)