This argument will use the example of parental love, although the point applies to any type of love.
A parent will love their child in at least two different ways. One is because the child is theirs, they carried and gave birth to them. This love comes from the fact that they made this person and allowed them to love, and also that they took care of them. This makes a sort of link between the parents and child.
Another related source and type of love is if they wanted a child. The decision to have a child is a difficult one, because it requires you to be willing to think and act in such a way that you are responsible for another human being and that your life goals are oriented to wanting to have a family. This decision shows that you are able to love someone unconditionally, in theory.
Related to these is the obligation one feels as the ones responsible for a person who needs others to help them, similar to adopting or taking care of someone. Guardians naturally will feel empathy towards the person they are protecting, which forges a link between them that goes beyond a professional relationship.
Parents naturally feel love for their children as a result of evolution, in order to make sure that they take care of their children. This type of love is essentially meaningless, it is simply an instinctually induced bias. This is the reason that parents think their children are amazing, beautiful, or skilled, even when they are not. This false pride is essentially just the bias of a parent who loves their children so much that they can not objectively judge anything related to the child. This is dangerous because it affects decisions the parent makes and can result in them making terrible mistakes. A parent should encourage their child on their achievements and encourage them to do better, but if the parent cannot objectively see their children’s limitations then they can’t help them to overcome them.
Related to this is obligation to your child as their guardian. Protecting your child or even giving your life for your child should be done out of an objective and reasonable motive, not because your brain is filled with chemicals telling you to. Sacrificing yourself for someone you love should be a rational decision, because if it isn’t then you’re just following arbitrary orders from your evolution, and that is not true love. All that is, is the same as why animals eat and reproduce, simply because they are compelled to. Whatever you would do for your child, including sacrificing your own life, must be done because you know beyond any doubt that it is the right thing to do. When you give your life simply because you feel so strongly that suddenly you “would do anything” for them just because they’re your child, you can become as dogmatic as religious or patriotic extremists. Sacrificing yourself and “doing anything” for your children isn’t necessarily bad, but it must be done for the right reason. Obviously in such a situation, the reason is less important than the act, except when the wrong reason makes you do the wrong thing.
These sources of love are not bad, but there are more important reasons to love someone. All the reasons listed above are causal, since they are simply facts that explain things that happened. You may choose to do some of these things such as having a child or choosing to protect someone, but the argument for love has to be the same whether or not you chose it. The reason you love your child should have nothing to do with whether you chose to have them. As such, the reason for these types of love need to be considered without relation to whether or not you chose these events to happen. Therefore, all the reasons above should be considered as love as a result of something that happened, regardless of whether or not you chose it to happen.
To explain this, consider the idea of loving your parents because of their family relation to you, or because they gave birth to you. Consider the following phrase, said in two different ways:
“You love them because they are related to you.”
“You only love them because they are related to you.”
While the first sentence seems to make sense, and in fact does make sense to a certain extent, the second sentence shows a related issue with that. This difference requires you to be open minded to understand it. Love should not simply be required as a matter of fact, if you only love someone because of things that happened, then your love is a result of events. This is essentially conditional love, not in that you have conditions for loving them that can change in the future, but because the cause for your love had conditions. The condition for obsessive maternal love is giving birth to the child. The condition for brotherly love is that the person is your fraternal brother. That is a relatively shallow love, as it is merely a consequence of a chain of events. If your parents only loved you because you were theirs, then they would stop loving you if they found out that you were not in fact theirs. This is not true love at all. It is in fact very disheartening to know that someone you care about only loves you because you are related, which can be something that you don’t even have control over.
The fact alone that someone gave birth to you is not sufficient for you to love them. An example of this is when a parent does not particularly want a child or does not really care about them once they are born. To take that to an extreme, an abusive and hateful parent does not necessarily deserve love simply because they gave birth to that person. Such a person might deserve love as a troubled human being, but as a terrible parent they are not owed any paternal love unless the child chooses to.
On the contrary though, if the parent is loving then the fact that a parent gave birth to a child adds to the reasons that the child should love their parents.
Another way to put this is through the following question:
Would you rather someone love you because fate made you related, or that they love you regardless of your relation and instead because of who you are?
Love as a result of fate is not bad. In can in fact add more to your love. However, I believe that true love, whether it be for a child, parent, spouse, or friend, requires part of that love to be willing, because you choose to love them regardless of everything else. Whatever might have happened between you and that person, whether it is good or bad, does not matter. You love someone because of all the good they have done, but most importantly because you decide that this person, because of who they are, is someone that you love.
Love should not be causal or deterministic, but it should be reasonable. The people you love might be inspired by what they do and what happens in your life that you can’t control, but love is deeper than just that. Beyond that, you love someone not only because of what they have done, but because of who they truly are. Most importantly, it should be you who chooses to love out of your own free will.
True love simultaneously has reasons, and yet no reason. You don’t choose who you can love, yet you choose whether or not you love them.
The reason we love is more than simply your relationship to someone or your obsession with them or obligation to them, it is both that we want to love them and that we naturally are in love with them.