This article seeks to compare Spinoza’s philosophy with Vygotsky’s psychology on the problem of consciousness: How should one define this entity of internal reflexivity, if one’s analytical point of departure is not personal and substantial thought, but social and interpersonal relation, constitutive of individual thought? One of the clearest definitions of consciousness Vygotsky gives is the following: “consciousness is the experience of experiences (soznanie est’ perezhivanie perezhivanii).” This conception of consciousness is very close to that of Spinoza who, defining it as “the idea of the idea,” explains the extent to which consciousness and affectivity are linked. We will therefore show in what sense consciousness, understood as Affect, is constituted by the social environment, and why we can identify degrees of consciousness or awareness in children, depending on whether the lived affect is more or less developed, that is, more or less active. And we will relate the power of reflexivity of consciousness to the power of reversibility of corporeal affections, starting with that of words.