When clouds cover the sky, we cannot see the pure nature of space. Likewise, when conceptual thoughts occupy the mind, we cannot see the pure nature of the mind. To see whether this is true, we can meditate so that the mind becomes relaxed and peaceful, and then there is room to develop compassion, love, and bodhicitta. But when our mind is occupied by conceptual thoughts and negative thoughts, there is no space to develop good qualities. Our mind becomes full of suffering and we cannot disentangle ourselves from confusion.
When our mind emphasizes positive, calming, and relaxing thoughts, it leaves no space for negative thoughts to arise. Then we can maintain a peaceful, harmonious mind regardless of external conditions. This becomes a matter of how much we habituate ourselves to the Dharma teachings.