Theism (issarakāraṇavāda) is the belief in an all-loving, all-powerful and all-knowing God who created and controls the universe.
It is one of the four false views (A.I,173), together with materialism (lokāyatavāda), kammic determinism (sabbaṃ pubbekatahetu) and randomism (ahetuvāda).
Buddhism's main objection to theism is that God's supposed attributes contradict each other.
If he (some gods are feminine, others have no gender) really created and controls everything then he must be responsible for all the suffering in the world. : `
If he really is the Controller, the Highest, Lord of All Beings, why is there so much deceit, lies, pride and unrighteousness?
If he really is the Controller, the Highest, Lord of All Beings, then he must be unrighteous and cruel, because it was he who made everything’ (Ja.VI,208).
In his Jātakamālā Āryasūra told a story of an ascetic who wore a fake monkey skin so that when people blamed him for killing the monkey he could highlight the contradictions in their beliefs.
When those who believed in a Supreme Being condemned him for killing an animal he said to them: `According to you, God is the creator and cause of everything.
But look! If God is behind everything, then it must be he who killed the monkey.
So how can you be so unfriendly as to blame me for the crime committed by another? If, on the other hand, God in his pity did not kill the monkey, then why do you so loudly proclaim that God is the cause of everything?
Further, my friend, why do you pray to and make offerings to Him for this and that, when He, the Self- Existent One, is the one doing your actions? You may well insist that it is you who is worshipping but surely it is He who is the true agent.
If it is God who does everything he must also do all evil. You can't make exceptions! So which of His qualities do you focus on when you worship and praise Him?
But if, on the other hand, you despise evil, insisting that God is not responsible for it, then you can't say everything is due to Him.’ (Jātakamālā 23,31-7)
If God is really omniscient this means that humans have no freedom and thus God's function as arbiter of right and wrong, rewarder of good and punisher of evil, becomes redundant. If God is really all-powerful and can stop massive disasters like earthquakes, floods and tsunamis but does not, he can not be all-loving.
From the Buddhist perspective, human spiritual consciousness could be said to move through three stages: polytheism, monotheism and non-theism, although, of course, not everywhere at the same time or amongst everyone in a particular society. Primitive peoples attributed different natural occurrences and forces to different deities. Later, all these were attributed to a single deity.
In its highest and most sophisticated stage, the human mind understands that things happen as a part of the order of nature and not because of a deity.
It is interesting to note that these three stages roughly correspond to the periods when people lived in tribes, when they were governed by autocratic monarchs and finally when democratic and scientific thinking became dominant. See Agnosticism.
Buddhism: A Non-theistic Religion, H. von Glasenapp, 1970.