According to Carveth Reid, the cause of any event is qualitatively, "the immediate, unconditional, irreversible, antecedent of effect" and qualitatively "equal to the effect."
Qualitative Marks of Cause:
(a) The cause is relative to a given event called an effect. Cause and effect are relative to each other. This means, effect is impossible without cause and impossible without effect. Both are dependent on each other. Again, the same cause can sometimes be a cause and sometimes as an effect.
(b) Cause and effect are always events of time. An event in time means a change in the current state of things. If there is a change in the current state of things, then the question of work-cause will come in our mind, why is there a change? Similarly, we also inquire into floods, wars, political revolutions and so on.
(c) Is inconsistent with the cause effect. Cause and effect are serially related. When two events occur sequentially, the antecedent is called the 'antecedent' and the following is called the 'consequent'.
(d) Is indiscriminate for the cause effect. Every effect has a cause. This cause always precedes the effect. This means that the cause is antecedent, but irregular response to the effect may not be the cause.
Quantative Marks of Cause:
According to the law of conservation of matter of energy the cause is equal to the effect. Because the quantity of mater and energy in the world is constant, it never increases or decrease but forms may be changed. So far as matter is concerned the effect is identical with the cause but the forms may be different. When certain quantity of Oxygen is combined with the certain quantity of Hydrogen in the form of water form is changed. But the weight of water is equal to the weight combining substance.
Again so bar as energy is concerned with the quantity of energy is equal to the cause. For example: When a moving body loses its motion it appears that the energy is lose. But actually it is converted into another energy viz. Heat follows so energy is quantity equal to the cause.
