Sometimes people think that the point of meditation is to stop thinking — to have a silent mind. This does happen occasionally, but it is not necessarily the point of meditation. Thoughts are an important part of life, and mindfulness practice is not supposed to be a struggle against them. It’s more useful to be friends with our thoughts than thinking them unfortunate distractions. In mindfulness, we are not stopping thoughts as much as overcoming any preoccupation we have with them.
Mindfulness is not thinking about things. (It is not “meditating on” some topic, as people often say.) It is a non-discursive observation of our life in all its aspects. In those moments when thinking predominates, mindfulness is the clear and silent awareness that we are thinking. I found it helpful and relaxing when someone said, “For the purpose of meditation, nothing is particularly worth thinking about.” Thoughts can come and go as they wish, and the meditator does not need to become involved with them. We are not interested in engaging in the content of our thoughts; mindfulness of thinking is simply recognizing we are thinking.
Gil Fronsdal, from About Mindfulness of Thinking