Miracles and medicine

I think many atheists, especially scientists, are conditioned to secularism because, in their observation, the natural world operates like a machine. 

And up to a point, that's consistent with Christian theology. Christian theology has a doctrine of ordinary providence. As a rule, natural events are governed by secondary causes. A chain of physical cause and effect. 

As a rule, a botanist wouldn't attribute a sickly plant getting better to divine intervention. As a rule, a veterinarian wouldn't attribute a sick horse getting better to divine intervention. 

However, let's consider miraculous answers to prayer. These are usually prayers for humans. If God intervenes more often in medical practice than botany, that's a reflection of the fact that more prayers are directed at sick humans.

But let's take a comparison. John Wesley once prayed for his horse:

Wesley was familiar with all the discomforts of the road. His horses fell lame or were maimed by incompetent smiths. Sometimes there were more serious accidents. In July 1743, he and John Downes rode from Newcastle to Darlington. They had young horses, which were quite vigorous the day before, but now both seemed unwell. The ostler went in haste for a farrier, but both animals died before they could discover what was the matter with them. In June, 1752, a young strong mare which Wesley borrowed at Manchester fell lame before he reached Grimsby. Another was procured, but he was “dismounted” again between Newcastle and Berwick. When he returned to Manchester, he found that his own mare had lamed herself whilst at grass. He intended to ride her four or five miles, but some one took her out of the ground. Another which he had lately bought ought to have been forthcoming, but she had been taken to Chester. In one journey his horse became so exceeding lame that it could scarcely set its foot to the ground. Wesley could not discover what was amiss. He rode thus seven miles till he was thoroughly tired, and his head ached more than it had done for months. He says, “What I here aver is the naked fact. Let every man account for it as he sees good. I then thought, ‘Cannot God heal either man or beast by any means, or without any’ Immediately my weariness and headache ceased, and my horse’s lameness in the same instant. Nor did he halt any more that day or the next. A very odd accident this also!” 

http://wesley.nnu.edu/?id=95

Although it could be coincidental, this seems to be a case of answered prayer. For the sake of argument, let's say that's the case. 

Back in the days when many Christians relied on horses for farming and transportation, more prayers would be directed at ailing horses. To the extent that God answered their prayers, God intervened more often on behalf of horses. In that event, veterinary science ought to make greater allowance for miracles. But there is less occasion for that today.

Likewise, if a Christian farmer prays for infested crops, and God answers his prayer, then God intervened on behalf of corn or wheat. In that event, a botanist ought to make allowance for a miracle. 

To some degree, what scientists observe concerning the presence or absence of miracles in their field may mirror what Christians generally pray for. Nature is more automatic when we have less occasion to pray about natural events. We pray for what we need.