To dwell in the here and now does not mean you never think about the past or plan responsibly for the future. The idea is simply not to allow yourself to get lost in regrets about the past or worries about the future. If you are firmly grounded in the present moment, the past can be an object of inquiry, the object of your mindfulness and concentration. You can attain many insights by looking into the past. But you are still grounded in the present moment.
Thich Nhat Hanh