Differentiating between formal positions condition and the conditioned (i.e. if-vector) as well as between the content’s exemplars (occuring in these positions, i.e. vector of relevance) and a direction of grammatical tenses (i.e. time vector) enables us to define two types of reasoning, based on the cause/effect relationship: deductive prediction and retrodiction (positive time direction) and abductive prediction and retrodiction (negative time direction). Although these predictions and retrodictions are formulated in form of conditionals, they are in fact elided expressions for reasons. A producer of deductive predictions and retrodictions picks up from a complex set of effects producing conditions one main condition, which, as a cause, is indicated in the antecedent. At the same time it is supposed that the effect indicated in the consequent is implied deductively. However, this holds only if the ceteris paribus principle (other things being equal), as well as the tacit set of true statements (the majority of which the producer need not know) are true.