The eight limbs form a sequence from the outer to the inner.
Postures, important in modern yoga as exercise, form just one limb of Patanjali’s scheme; he states only that they must be steady and comfortable. The main aim is kaivalya, discernment of Purusha, the witness-conscious, as separate from prakriti, the cognitive apparatus, and disentanglement of Purusha from its muddled defilements.