Yes, the emptying of the mind is the style of oriental meditation. In contrast, there is an old tradition of Christian meditation which attempts to fill the mind completely with one concept.
For example, in the medieval Lectio Divina (http://en.wikipedia.org/wiki/Lectio_Divina), one takes a few words of scripture and repeats them and considers them and ponders them for many minutes. The Cloud of Unknowing recommends doing something similar with the concept of God, or with a simple word such as "love".
This is actually a pretty tough mental exercise to do for even just 20 minutes.
For example, in the medieval Lectio Divina (http://en.wikipedia.org/wiki/Lectio_Divina), one takes a few words of scripture and repeats them and considers them and ponders them for many minutes. The Cloud of Unknowing recommends doing something similar with the concept of God, or with a simple word such as "love".
This is actually a pretty tough mental exercise to do for even just 20 minutes.