In a letter written in Jaffa in 1905, Rav Kook responded to questions concerning evolution and the geological age of the world. He put forth four basic arguments:
1. Even to the ancients, it was well known that there were many periods that preceded our counting of nearly six thousand years for the current era. According to the Midrash (Bereishit Rabbah 3:7), “God built worlds and destroyed them,” before He created the universe as we know it. Even more astonishing, the Zohar (Vayikra 10a) states that there existed other species of human beings besides the ‘Adam’ who is mentioned in the Torah.
2. We must be careful not to regard current scientific theories as proven facts, even if they are widely accepted. Scientists are constantly raising new ideas, and all of the scientific explanations of our time may very well come to be laughed at in the future as imaginative drivel.
3. The fundamental belief of the Torah is that God created and governs the universe. The means and methods by which He acts, regardless of their complexity, are all tools of God, Whose wisdom is infinite. Sometimes we specifically mention these intermediate processes, and sometimes we simply say, ‘God formed’ or ‘God created.’
For example, the Torah writes about “the house that King Solomon built” (I Kings 6:2). The Torah does not go into the details of Solomon speaking with his advisors, who in turn instructed the architects, who gave the plans to the craftsmen, who managed and organized the actual building by the workers. It is enough to say, ‘Solomon built.’ The rest is understood, and is not important. So too, if God created life via the laws of evolution, these are details irrelevant to the Torah’s central message, namely, the ethical teaching of a world formed and governed by an involved Creator.
God limits revelations, even from the most brilliant and holiest prophets, according to the ability of that generation to absorb the information. For every idea and concept, there is significance to the hour of its disclosure. For example, if knowledge of the rotation of the Earth on its axis and around the sun had been revealed to primitive man, his courage and initiative may have been severely retarded by fear of falling. Why attempt to build tall buildings on top of an immense ball turning and whizzing through space at high velocity? Only after a certain intellectual maturity, and scientific understanding about gravity and other compensating forces, was humanity ready for this knowledge.
The same is true regarding spiritual and moral ideas. The Jewish people struggled greatly to explain the concept of Divine providence to the pagan world. This was not an easy idea to market. Of what interest should the actions of an insignificant human be to the Creator of the universe? Belief in the transcendental importance of our actions is a central principle in Judaism, and was disseminated throughout the world by her daughter religions. But if mankind had already been aware of the true dimensions of the cosmos, and the relatively tiny world that we inhabit, could this fundamental concept of Torah have had any chance in spreading? Only now, that we have greater confidence in our power and control over the forces of nature, is awareness of the grandiose scale of the universe not an impediment to these fundamental ethical values.
To summarize:
Ancient Jewish sources also refer to worlds that existed prior to the current era of six thousand years.
One should not assume that the latest scientific theories are eternal truths.
Some ideas are intentionally kept hidden, as the world may not be ready for them, either psychologically or morally.
(Gold from the Land of Israel pp. 23-25. Adapted from Igrot HaRe’iyah vol. I, pp. 105-107)