>If you erased your memory of being a parent with time travel, you actually CAN not be a parent.

We're talking about memory erasure plus accurate knowledge of the future. The combination is different from memory erasure by itself. Not knowing what parenthood is like, I would choose to become a parent - I know this because that's what actually happened. Accurate knowledge of the future would not change that decision, for the reasons I gave.

>You would tell your past self that you would be less happy, but you would be able to convince him to have a kid regardless as if he could understand your reasoning through you simply communicating vocally to him. My question to you is why didn't you try communicating this knowledge to me?

- I'm not convincing him, I'm merely conveying information. I have nothing to gain or lose, and I already know what he's going to do absent the information.

- He could understand my reasoning because he's me, I know everything about him, and he trusts me implicitly because I have nothing to gain by deceiving him.

- I can't trust you to convey my thinking accurately because you are biased by your own worldview, as am I. He can't trust you either. Therefore any information you give him would be imperfect, tainted by the impossibility of communication between different people. My point is that only that kind of imperfect information might change his behaviour.

>your words would not convince me to have a kid if the result of everything you said meant that I would be significantly unhappier.

Who said anything about convincing you? Past me is already inclined to have a child, whereas you appear to be quite against it. Moreover, it would be very irresponsible of me to convince you to act against your own self-interest. But I will attempt it...

Some axioms:

1. A quiet, uneventful, comfortable life with amiable companionship is the epitome of happiness.

2. Happiness is not the only measure on which the quality of a life can be judged.

3. It is possible for two equally logical processes with different sets of priorities to arrive at contrary conclusions.

Say that tonight, Mephistopheles appears in your room and offers you the chance to travel throughout space and time and learn all the secrets of the universe. Being all-knowing, he also tells you with undeniable authority that saying yes will make you somewhat less happy than saying no. What would you say? I would say yes without question. My curiosity is more important than my happiness.

Say that tonight, Beelzebub appears in your room and offers to take 50 points off your IQ in exchange for serene ignorance of all that goes on around you. You will live out the remainder of your life in physical comfort and absolute, beatific bliss in a centre for the severely disabled. What would you say? I would say no, without question. My ability to perceive the world is more important than my happiness.

I use the metaphors of knowledge and curiosity because I expect they will appeal to your sensibilities. The set of priorities that led me to becoming a parent is unique to me, and I doubt you would find it convincing, so I will not spend time typing it out. But perhaps the metaphor will open your mind to the idea that happy is not always the best thing you can be.