We may say in all tranquility that Spiritism is a religion especially because Kardec remarked that philosophically Spiritism is a religion, and we are honored of that, for it is the doctrine that lays the foundations of the fraternity ties and of the communion of thoughts not in a simple convention, but rather on the most solid of the foundations: the very laws of Nature. He adds that for many religion is incompatible with what Kardec affirms for the term "religion" is inseparable from the notion of cult, and that only evokes an idea of form, with which the Spiritism has not relation at all. If he had proclaimed a religion, the public would not see anything in it but a new version of the relentless principles in matters of faith, a priestly hierarchy with its procession of conventions, ceremonies and privileges; it would not distinguish it from the ideas of mysticism and the mistakes against which one is frequently very well prepared
Not introducing any of the characteristics of a religion, in the usual meaning of the word, Spiritism neither could nor should be adorned of a title about whose meaning there would be unavoidably misunderstandings. That is why it claims to be simply a philosophical and moral doctrine.
It is imperative to consider that the greatest difference between Spiritism and the ordinary religions is that the latter usually interpret the Lord of Life as a supreme being, creator of everything that exists, yet bearing human characteristics (anthropomorphism). Philosophically the Spiritualistic Doctrine enunciates it as "the Supreme Intelligence, the Primary Cause of all things" attributing to it "eternity, immutableness, immateriality, unicity, omnipotence and sovereign justice and kindness" which evidently excludes any anthropomorphic trait.
Another basic difference is in the way the Spiritualistic Doctrine understands that the search of God is to be performed without any special character of moral rules or satisfaction of formal and external cults of many orders. In the spiritualistic hordes its postulates do not couple to practices such as baptism, confirmation, communion, confession; participation in exotic cults, rituals, ceremonies; performing of corporal gestures; recitation of formulas and prayers; adoration of varied images and objects; promises, penitences, fasts, etc...
The Spirits explain that the communion of the creature to the Creator is basically made by the coherence of his/her behavior with certain moral codes and any measures of external order are considered dispensable.
Kardec's propositions also differ as of the matters of moral order. Spiritism holds them as supreme, mainly those suggested by Jesus, and which fall within the precept of "love thy neighbor". On the other hand, traditional religions tend to include - or not - those that have the force of evangelical norms, or to partially include them, or to add others to them, or to alter them from the original interpretation, etc. Thus, the final difference appears in the way those ethical rules are justified
Nowadays, modern Christianity "justifies" the moral norms that it proposes, evoking the authority of this or that individual or institution; they are dogmas, therefore articles of faith to be accepted without any questioning. Thinking about the logical mechanics of life, there will come a day when the faithful interpreters of Kardec will be precious helpers in the transformation of the theological parliaments into spirituality academies. Especially because Spiritism bases its ethical precepts in the knowledge that it scientifically reaches the consequences of the human actions along the unlimited existence of the beings (reincarnations), conjugated with the theological clause that all long for happiness. However, in its postulates there is no room for dogmas or dogmatic injunctions, only for the free and rational investigation of the facts.
Spiritism's mission is precisely explaining to us the immortality, the communication of the "dead", the reincarnation, the habitability in other planets.
It is the reality that appears to us, since the very beings from beyond grave come to describe to us the situation in which they are and to tell us what they do, allowing us to watch all vicissitudes of the new life that they live there and showing us, through mediunity, the inevitable fate to which we are bound, according to our deeds.