"Of all forms of caution, caution in love is perhaps the most fatal to true happiness."
Induction is the name for the kind of logic that comes from the ground up--where conclusions are drawn from generalizing about groups of isolated experiences. Induction is the basis for science, and this kind of reasoning is incredibly natural in humans. We use it to get dressed every day: we look out the window, decide what the weather is like, and dress accordingly. If it's cloudy and we know it's January, we put on a sweater because in the past that has usually indicated that it's cold out.
The problem with induction is that you are generalizing. You can't ever be 100% certain that something is true. Even in January when it's cloudy, it could be 70 degrees outside; it's unlikely, but it could be. Using induction to make decisions is reliable, but it also makes it harder to identify and react appropriately to the abnormalities and outliers; and the truly insipid part of induction is that relying on it too heavily can cause you to change your behavior in response. If you have only ever seen white swans, you may not even recognize a black one. You won't be looking for it, and you won't be able to add the new information and adjust your generalization accordingly.
Most of the time this isn't a problem; if it happens to be a freak warm day in January you can just go change your sweater. Mistakes due to the problem of induction are mostly negligible. But I want to talk about people.
What happens when most of your experience has led you to believe that people are bad, or at best negligent, and can't be trusted? Most of the time you will probably be right in your behaviors and assumptions, but you will also, without noticing it, change your own behavior to compensate for your generalization. You will be less willing to go out of your way for others, less willing to accept new people into your life, and less likely to forgive people for their mistakes. All of which are reasonable ways to conduct your life. In many ways these behaviors are probably worth the few exceptions that slip through the cracks in terms of the pain and loss they spare you.
But what about the real exceptions?
What about the people who will bring joy into your life, who really do care for you, and who may have a few sad histories they've generalized from, themselves? I don't mean the guy on the street who really did need some change for a bus fare because he just got mugged; I'm talking about the man who really wants to be your friend and support you in all the ways he can; somebody who could be your lifelong friend--somebody who is not worth losing, no matter how many times you avoid being cheated out of your money by others. The kind of friend whose value is immeasurable. How does your automatic behavior affect them?
Be careful with induction. People are not a deck of cards, and a whole lifetime's experience is not enough to reliably predict a person's shade of grey. Be careful with your money and your time and your heart, but take more care that you do not let your pain prevent your joy. Take care that you do not look only for what you have already found.