Shaw opposes Darwin that everything in life has created by accident. He states that even behind evolution there is a will. But how can we say that animals have will? It is true that giraffe stretches its neck to get the more tender leaves at the top of the tree and it causes giraffe to have longer neck. However, this change has happened because of giraffe's instinct not its will. He believes that it is the will behind evolution that causes change and creating of new tissues as he says "The will to do anything can and does, at a certain pitch of intensity set up by conviction of its necessity, create and organize new tissue to do it with". This might be true for human being who has the will to change his/her situation in life, but in my opinion is not the case for animals.
Shaw affirms Lamarck's theory of evolution but neither Darwin's theory of evolution nor Bergson's philosophy of creative evolution as he says "Lamarck, whilst making many ingenious suggestions as to the reaction of external causes on life and habit, such as changes of climate, food supply, geological upheavals and so forth, really held as his fundamental proposition that living organisms changed because they wanted to. As he stated it, the great factor in Evolution is use and disuse." In my opinion, Darwin's theory of evolution is problematic for Shaw because then Shaw has to accept that nothing in life has a purpose behind it and he has to question himself that what the purpose of living this life is. Therefore, Shaw's problem with the theory of evolution and Darwin is that Darwin did not mention that there is a will and purpose in evolution process and it is all random and accident.