Popper (1902-1994) was a British philosopher and a professor at the London School of Economics. Because he is regarded as one of the greatest philosophers of science of the 20th century, what he had to say about philosophical materialism and Darwinism is of utmost importance to the down and dirty war of attrition waged by methodological and ontological naturalists against creationists and intelligent design adherents.
Though Popper favored evolutionary theory and natural selection, he also forthrightly stated that Darwinism is not a testable scientific theory but rather a metaphysical research program. By this he means that not only is Darwinism metaphysical (immaterial/spiritual), but so are its' two most important foundations, classical empiricism and the observationalist philosophy of science that grew out of it.
Empiricism is a theory of knowledge that contradicts itself by asserting that human knowledge comes only or primarily via sensory experience rather than the mind while observationalism asserts that human knowledge and theories must be based on empirical observations....instead of the mind. For this reason, Popper argued strongly against empiricism and observationalism, saying that scientific theories and human knowledge generally, is conjectural or hypothetical and is generated by the immaterial creative imagination.
In other words, all three theories originated in the immaterial mind, a power of which is imagination. As spirit (intellect and will) is the citadel of the soul, then Darwinism, empiricism, and observationalism are spiritual.
The Founding generation knew that mind is a power of soul, and imagination the power by which mind conceives. In Noah Webster's American Dictionary of the English Language, 1828, soul and imagination are respectively defined as:
1. Soul: "The spiritual, rational and immortal substance in man, which distinguishes him from brutes; that part of man which enables him to think and reason."
2. Imagination: "...the power or faculty of the mind by which it conceives and forms ideas of things communicated to it by the senses....The business of conception (and the) power of modifying our conceptions, by combining the parts of different ones so as to form new wholes of our own creation...(imagination) selects the parts of different conceptions, or objects of memory, to form a whole more pleasing, more terrible, or more awful, than has ever been presented in the ordinary course of nature."
In short, Darwinism, classical empiricism and the observationalist philosophy of science claim to be what they are not in order to obtain an advantage over the Genesis account of creation and intelligent design by imposition of immoral means. We need to realize that the most zealous and outspoken defenders of this false science are arrogant sophists who hate truth and reality and mean to keep it out.
This philosophical insight is actually reduced to an experimentally reproduceable phenomenon in cases where the Heisenberg Uncertainty Principle applies.
Even Paul acknowledged that man has a spirit, a soul, and a body. The soul is not the spirit. The mind is an aspect of the soul and even a bird has a mind, but in humans the mind of the soul can be informed via spiritual level reasoning.