Poorly constructed graphs can make data difficult to discern and thus interpret. Other religious practices sought to discern the gods' will or seek their knowledge. You must be able to discern this. Envoys possess total recall and are able to discern subtle patterns within seemingly unrelated events. The covert characteristics are by definition difficult to discern and not immediately apparent. Causes are varied and can be difficult to discern. However, some fish can discern polarized light, demonstrating that they possess some linear photoreceptors. Some psychologists have the ability to discern hidden meaning from person's facial expression. Elephants are thought to be able to discern relatives even from their remains. K'awiil, although it now is difficult to discern. The origins of the black dog are difficult to discern. While we can discern a great deal through reason, we are ultimately forced to gamble. How can we discern that there are guarantees of an authentic Christian education? Instrumentalism exhibited by "scientists" often does not even discern unobservable from observable entities. Their effects on sex trafficking are difficult to discern.