"I am willing to believe that my unobtainable sixty seconds within a sponge or a flatworm might not reveal any mental acuity that I would care to call consciousness. But I am also confident [...] that vultures and sloths, as close evolutionary relatives with the same basic set of organs, lie on our side of any meaningful (and necessarily fuzzy) border and that we are therefore not mistaken when we look them in the eye and see a glimmer of emotional and conceptual affinity."

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Henceforward the Christian Churches having a form of godliness, but denying the power thereof, came into the hands of the Encratites: and the Heathens, who in the fourth century came over in great numbers to the Christians, embraced more readily this sort of Christianity, as having a greater affinity with their old superstitions, than that of the sincere Christians; who by the lamps of the seven Churches of Asia, and not by the lamps of the Monasteries, had illuminated the Church Catholic during the three first centuries.

— Isaac Newton