The knowledge of one’s own mind is neither a religion nor philosophy. Even though contemplative traditions have been existing since millennia in spiritual context, the nature of one’s own mind can be explored regardless one’s religious, moral, or scientific believes. Mind cannot be directly observed from outside, therefore, we need contemplative methods to observe it from inside. Certain things are invisible just because we don’t know where to look, what to notice, and lack proper instruments. Meditation is a way to develop mental optics as well as a skill how to use it.
It's not just about experiencing special states of mind but rather about using special states to flashlight things we miss in our ordinary states. Missing not because of their absence but because we don't know where to look.