Imagine you know someone who has never - even once - tasted honey, but whose hobby is learning all she can about it.
She has spent countless hours studying honey. She knows all about how it is produced, how to care for the bees and make sure they have access to the right kind of flowers, and how to harvest it and refine it so it is ready for the table. On top of that, she's read numerous accounts of what honey tastes like from a variety of different sources. She is completely fascinated by these descriptions.
Our hypothetical friend knows everything there is to know about honey, but she's never tasted it for herself. There's no doubting that our friend knows a great deal, but doesn't the average joe who has actually tasted the goods have the more crucial understanding of honey? Isn't her understanding of honey disastrously incomplete, even flawed? And even more importantly, though we have to admit she is genuinely passionate about honey - we could even say she loves the stuff - we'd have to also admit that something important is missing, that she can't really love honey, at least not properly.
This strange anecdote sheds light on what's going on in Jonathan Edwards' book, Religious Affections. By affections, Edwards means the "vigorous and sensible exercises of the inclination and will of the soul" (96). He's talking about our positive emotional responses to God - especially things like love and joy. We all experience affection for a variety of different things. If you're a Christian you must have some kind of affection for God. But our affections aren't always what they seem - they can be deceiving.
Take our honey-obsessed friend. She absolutely loves honey, and experiences great joy while learning and discussing the topic. But something crucially significant is lacking. This is a person who sincerely loves honey, but a five year old who has ever squeezed a translucent golden plastic bear has the ability to love honey in a deeper, more important way; he is able to love honey the way it is actually meant to be loved.
This is because if a person is going to love someone or something, he or she first has to have some experience of it. Moreover, a great many things are supposed to be experienced in one or more appropriate ways, and our experience of them is flawed if we try to experience them in different ways. For instance, I would recommend that you taste honey - don't just read about it. Likewise, I'd suggest you read a novel, and I would discourage you from attempting to taste it.
It's the same in religion. But if touch is the appropriate way to experience play-dough, and sight is the appropriate way to experience the Mona Lisa, what is the appropriate way to experience God so that He might raise our affections? What 'eyes' do we have with which to 'see' God, so that we might admire him in appropriate love and joy?
Edwards suggests that the Holy Spirit gives us something he calls the 'spiritual sense' that makes these proper, 'gracious' affections possible. It's a sense similar to sight or touch or taste, but instead of enabling our experience of light or texture or flavor, it enables us to experience God's grace. Grace, after all, is no ordinary thing. It's utterly unique and new, and we can't appreciate it adequately with our ordinary capacities: sensory or emotional or mental. If we are going to love God truly the way God is supposed to be loved, we need new tools, and that's what the 'new sense' provides.
You can love the idea of God, and you can receive joy when thinking upon the things of God. You can have great passion and affection while learning about God, your heart can become excited upon hearing the Christian message - the good news of God's love in Jesus. But this is quite a different thing than loving God himself. Real love and passion for God, according to Edwards, means discovering new eyes with which to see, new ears with which to hear. We need a new, spiritual sense. Edwards seems to think this can come to us only as a gift.