Unclear Deliberation Is a Lack of Meditative Concentration

Everyone should train their thinking well and not deviate too far from the right direction. If one's thinking is unclear, it must be due to a lack of meditative concentration (samādhi), and then one must strive to cultivate meditative concentration. If meditative concentration cannot be cultivated well, examine whether you lack merit, or whether your observance of precepts is not good enough, or whether your habitual tendencies are too heavy, or whether there are obstacles on the physical level.

Many people lack meditative concentration; their power of concentration is insufficient, so their thinking cannot keep up, and they cannot gain determination (adhimokṣa) regarding much of the Dharma—they cannot understand it. Their practice gradually falls behind, lagging behind others. Everyone must strive to find their own sticking point, to find their own shortcomings and deficiencies, and after finding them, think of ways to improve. Looking back at oneself, checking for gaps and patching up leaks—this is itself a form of diligence.

If one's power of concentration is even slightly lacking, contemplative practice (vipaśyanā-caryā) cannot reach its target, and then what one says has no evidence and is not necessarily the truth of reality. Therefore, as long as one's power of contemplative practice is not good enough, one should not assert one's own views with certainty.