Buddhism

Buddhism is a philosophical religion based on the teachings of Gautama Buddha. The primary goal of Buddhism is the attainment of enlightenment, a realization of the true nature of the universe as it pertains to sentient beings. This enlightenment involves the recognition that life is, to varying degrees, an illusion - a complex web of interdependent causes and effects. This doctrine is the foundation for the Buddhist concept of reincarnation.

The Four Noble Truths

 * 1) Suffering: Suffering exists in nearly every aspect of life
 * 2) The origin of suffering: Suffering is due to craving and is responsible for the endless cycle of reincarnation
 * 3) The cessation of suffering: Eliminating this craving will eliminate suffering
 * 4) The way leading to the cessation of suffering: The "Middle Way" or "Noble Eightfold Path" leads to the elimination of craving

The Noble Eightfold Path

 * 1) Right View - Realizing the Four Noble Truths
 * 2) Right Intention - Commitment to mental and ethical growth in moderation
 * 3) Right Speech - One speaks in a non hurtful, not exaggerated, truthful way
 * 4) Right Action - Wholesome action, avoiding action that would hurt others
 * 5) Right Livelihood - One's job does not harm in any way oneself or others; directly or indirectly
 * 6) Right Effort - One makes an effort to improve
 * 7) Right Mindfulness - Mental ability to see things for what they are with clear consciousness
 * 8) Right Concentration - State where one reaches enlightenment and the ego has disappeared

Buddhism as an atheistic religion
While some Buddhists view the Buddha as a deity, or similar, Buddhism does not necessarily include any concept of a god or god worship. The primary focus is on the personal journey toward the "correct" understanding of the nature of the universe and one's self. The absence of a positive belief in a god means that most Buddhists could be categorized as atheists, though that label is insufficient to describe the bulk of their beliefs.

Buddha specifically refused to answer a number of questions which are usually foundational to theistic religions.
 * Whether the world is eternal or not
 * Whether the world is infinite or not
 * Whether the body and the soul are one and the same or not
 * Whether the tathāgata (Buddha) exists after death, or not, or both does and does not, or neither does nor does not.

To Buddha, those questions were irrelevant and possibly counter-productive.

Rational objections to Buddhism
While personal growth and peaceful co-existence are laudable goals and meditation may be enjoyable and beneficial; Buddhism includes some unsupported assertions which deserve critical examination.

Karma
Karma, literally "action" is the Buddhist belief in a universal system of cause and effect. The results of karma are not seen as punishments or rewards but rather the natural results of actions. It is a concept that makes the universe appear more just, since all things that one is born with (that is usually out of one's hands) is deserved. However, there is little evidence for karma apart from wishful thinking. Also, Karma doesn't ultimately make the universe more just because a being is born with no memory of past lives. A baby born with a birth defect doesn't deserve it because of a previous incarnation, since that baby has no link to the other being besides the karma itself.

Rebirth
Buddhism denies the existence of an eternal essence or soul, and as such doesn't contain the belief in reincarnation as held by Hinduism. In place of reincarnation, Buddhists believe in a concept called "rebirth" which refers to the continuing of a personality (Samsara).

One could ask, "What is it then that is reborn, if there is no-soul?". Oftentimes, Buddhists will answer that a persons "habit-energy" or karma is passed on, but all answers to this question are very nebulous.

Also, there is little to no evidence of rebirth (aside from the Buddha and others who claim to be able to remember them) and it seems to be an empty theory. Buddhism requires the system of rebirth/karma to be complete, otherwise Nirvana could be attained by dying.

Some may argue that the whole idea of desiring to end rebirth is self-contradictory (since rebirth is stopped by ending desire) however Buddhist apologetics does deal with this. "Desire" as understood by the 4 Noble Truths, is deemed trishna and means wanting something that will not lead to satisfaction. Desiring Nirvana isn't a normal desire, because it is something that if attained, would be wholly and permanently satisfying.

Enlightenment
The pursuit of knowledge and understanding is accepted, nearly ubiquitously, as a worthwhile goal but there's simply no reason to assert that any "ultimate understanding" is attainable by personal reflection. While it may be impossible to achieve an ultimate understanding by any method, the most consistently reliable path to understanding has proven to be scientific investigation.

The idea of enlightenment, that meditation and quiet reflection will somehow allow the universe to reveal itself to the individual, is another unsupported assertion and, like reincarnation, most likely reflects the wishful thinking of sentient beings who crave understanding.