# "If I am going to" for time travel

Imagine a time traveller tells you that you are going to kill somebody or commit some other crime and that you are a bad person. Would it sound correct if I said in such a situation the following sentence?

I guess, If I'm going to do that, I really am a bad person.

I should add that I want to convey that I believe I am a bad person now regardless of your opinion on the philosophical question whether I could be called a bad person prior to the actual crime. Besides, I am aware that this is not a "normal" conditional sentence.

• +1 This is an entirely "normal" conditional. As JavaLatte says, there are no grammatical constraints on the time references in inferential conditionals, only semantic constraints, because you're concerned with logical inference not cause-and-effect. Commented Apr 22, 2016 at 10:34
• Even on StackExchange there are several WWWs dealing with science, and science fiction, in general and time travel specifically. This Question might be worth asking there but if you're looking purely at language, and English in particular, the time travel part makes no difference at all. Consider anyone catching you going equipped for burglary, or about drive a car when you've been drinking… Why would you not then confess: "If I'm going to do that, I really am a bad person…" Commented Jun 3, 2020 at 21:25

We use if about something that is a matter of fact when we want to infer something from it.

Imagine that you really can't remember whether you have paid your electricity bill. You look in the household file and find the receipt for payment. You would say to somebody:

I guess, if the receipt is here, I must have paid the bill.

I guess, if the receipt is here, I really did pay the bill.

It should not matter whether the fact is historical, current or future: it's a fact, and you can still infer something from it. Consider this sentence, which infers current state of mind from a future fact: note that the colon fulfils the clause-connecting role in place of if.

I'm going to do a bungee jump tomorrow: I must be crazy!

Your sentence is therefore a reasonable way of expressing the fact and what you infer from it.

I guess, If I'm going to do that, I really am a bad person.