بِثُبُوتِ بَعْضِ الْأَشْيَاءِ بِالْعِيَانِ، وَبَعْضِهَا بِالْبَيَانِ
Some things are established by direct observation and others by explanation or proof.
ʿIyān is immediate encounter or perception; bayān involves a reasoned account or supporting evidence. Not every knowable matter must be seen directly.
Seeing a book on a desk gives one kind of knowledge. Learning its authorship or a past historical event may depend on reliable evidence and reports.
Different routes to knowledge do not invalidate knowledge itself. The claim is modest but decisive: some realities genuinely can be known.