Can the efficacy of prayer be measured scientifically?
Personally, I would be a bit skeptical of any scientific study that claimed to have found a clear relationship between prayer and “desired outcome”. I’m of the opinion that this understanding of prayer (a mere tool for getting what we desire) is fundamentally flawed.
This is the same misunderstanding that Dawkins makes with his ”God Hypothesis” paradigm (i.e. “the existence of God is a scientific hypothesis like any other“). This viewpoint takes a very small view of God (and, by extension, of prayer). Rather than acknowledging God as the ultimate Source of all knowledge and human experience, it seeks to detect the existence of God as an entity within the physical universe - like one might detect dark matter or alpha particles. It regards God as a variable within a system rather than the Creator and Sustainer of the system itself.
In his book “Miracles” (buy it HERE, or check out my review HERE), C.S. Lewis offers the following commentary on free will, divine foreknowledge, and the efficacy of prayer. His model includes some important qualifiers and details that I’ve glossed over, but this excerpt conveys the basic idea:
“Suppose I find a piece of paper on which a black wavy line is already drawn, I can now sit down and draw other lines (say in red) so shaped as to combine with the black line into a pattern. Let us now suppose that the original black line is conscious. But it is not conscious along the whole length at once – only on each point on that length in turn.
Its consciousness in fact is travelling along that line from left to right retaining point A only as a memory when it reaches B and unable until it has left B to become conscious of C. Let us also give this black line free will. It chooses the direction it goes in. The particular wavy shape of it is the shape it wills to have. But whereas it is aware of its own chosen shape only moment by moment and does not know at point D which way it will decide to turn at point F, I can see its shape as a whole and all at once. At every moment it will find my red lines waiting for it and adapted to it. Of course: because I, in composing the total red-and-black design have the whole course of the black line in view and take it into account. It is a matter not of impossibility but merely of designer’s skill for me to devise red lines which at every point have a right relation not only to the black line but to one another so as to fill the whole paper with a satisfactory design…
It is never possible to prove empirically that a given, non-miraculous event was or was not an answer to prayer. Since it was non-miraculous the sceptic can always point to its natural causes and say, ‘Because of these it would have happened anyway,’ and the believer can always reply, ‘But because these were only links in a chain of events, hanging on other links, and the whole chain hanging upon God’s will, they may have occurred because someone prayed.’ The efficacy of prayer, therefore, cannot be either asserted or denied without an exercise of the will – the will choosing or rejecting faith in the light of a whole philosophy. Experimental evidence there can be none on either side. In the sequence M.N.O. event N, unless it is a miracle, is always caused by M and causes O; but the real question is whether the total series (say A-Z) does or does not originate in a will that can take human prayers into account.
This impossibility of empirical proof is a spiritual necessity. A man who knew empirically that an event had been caused by his prayer would feel like a magician. His head would turn and his heart would be corrupted. The Christian is not to ask whether this or that event happened because of a prayer. He is rather to believe that all events without exception are answers to prayer in the sense that whether they are grantings or refusals the prayers of all concerned and their needs have all been taken into account. All prayers are heard, though not all prayers are granted. We must not picture destiny as a film unrolling for the most part on its own, but in which our prayers are sometimes allowed to insert additional items. On the contrary; what the film displays to us as it unrolls already contains the results of our prayers and of all our other acts. There is no question whether an event has happened because of your prayer. When the event you prayed for occurs your prayer has always contributed to it. When the opposite event occurs your prayer has never been ignored; it has been considered and refused, for your ultimate good and the good of the whole universe. (For example, because it is better for you and for everyone else in the long run that other people, including wicked ones, should exercise free will than that you should be protected from cruelty or treachery by turning the human race into automata.) But this is, and must remain, a matter of faith. You will, I think, only deceive yourself by trying to find special evidence for it in some cases more than in others.”