Today, in a time when people don’t even know their neighbors’ names, I think your question is very valid.  Especially if you and your romantic interest didn’t grow up together in the same town, don’t know each other’s families, don’t attend the same church, don’t have friends in common or don’t work together, etc.  If this is the case, then there aren’t a whole lot of options left for how to get to know one another other than dating.

And so that leads me to a question regarding your question.  You ask, “Is casual dating okay for a single Christian?”  And I ask, “What do you mean by the descriptor casual?” 

Maybe you are referring to the initial time period of dating when you’ve just started going out and are getting to know one another—up until the point that you know you want to get serious with someone.  And so you would then move from being casual to serious in your dating relationship.  This is how I’m interpreting your use of this term. 

Whether dating is casual or serious, I think it can be potentially dangerous when two people are not on the same page as it relates to intent.  It seems as though one of the involved parties is always more interested—and his/her heart more invested—than the other.  My advice would be this:  If you know that you will never be interested in moving from casual to serious dating, then it’s time to have a DTR (define the relationship) talk.  In other words, what are you both thinking and where do you each want the relationship to go?

The point that you realize whether it is only a casual relationship or has the potential to become a serious relationship is the point at which you must either both agree to have a casual relationship (until one party feels otherwise), end the relationship, or move forward to a more vested level (serious). 

You must take into account the feelings of the other party involved.  Try looking at it from this way:  if you were dating someone who knew that he/she was only interested in a casual dating relationship with you—and you were feeling more in the serious vein—would you want to know?  Probably so.  And you would probably want to guard your heart.

• “Be devoted to one another in brotherly love.  Honor one another above yourselves” (Romans 12:10).
  
• “Do nothing out of selfish ambition or vain conceit, but in humility consider others better than yourselves" (Philippians 2:3).
  
• “Be imitators of God, therefore, as dearly loved children and live a life of love, just as Christ loved us and gave himself up for us as a fragrant offering and sacrifice to God" (Ephesians 5:1-2).

You may or may not be in a casual dating relationship right now.  But if you are, can you say that you are taking the above verses into account in how you treat the person you are dating?  Are you caring about the other person’s feelings and interpretations of your actions and motives just as much as you are your own?  Do you care that the other party will not get hurt and that you will not mislead him/her?