E2P21S
Scholium — Part II
Latin
Hæc propositio longe clarius intelligitur ex dictis in scholio propositionis 7 hujus; ibi enim ostendimus corporis ideam et corpus hoc est (per propositionem 13 hujus) mentem et corpus unum et idem esse individuum quod jam sub cogitationis jam sub extensionis attributo concipitur; quare mentis idea et ipsa mens una eademque est res quæ sub uno eodemque attributo nempe cogitationis concipitur. Mentis inquam idea et ipsa mens in Deo eadem necessitate ex eadem cogitandi potentia sequuntur dari. Nam revera idea mentis hoc est idea ideæ nihil aliud est quam forma ideæ quatenus hæc ut modus cogitandi absque relatione ad objectum consideratur; simulac enim quis aliquid scit, eo ipso scit se id scire et simul scit se scire quod scit et sic in infinitum. Sed de his postea.
English (Elwes 1883)
This proposition is comprehended much more clearly from what we have said in the note to II. vii. We there showed that the idea of body and body, that is, mind and body (II. xiii.), are one and the same individual conceived now under the attribute of thought, now under the attribute of extension; wherefore the idea of the mind and the mind itself are one and the same thing, which is conceived under one and the same attribute, namely, thought. The idea of the mind, I repeat, and the mind itself are in God by the same necessity and follow from him from the same power of thinking. Strictly speaking, the idea of the mind, that is, the idea of an idea, is nothing but the distinctive quality (forma) of the idea in so far as it is conceived as a mode of thought without reference to the object; if a man knows anything, he, by that very fact, knows that he knows it, and at the same time knows that he knows that he knows it, and so on to infinity. But I will treat of this hereafter.
Modern English
This proposition is understood far more clearly from what was said in the scholium to Proposition 7 (E2P7S). There we showed that the idea of the body and the body itself, that is (E2P13), mind and body, are one and the same individual, conceived now under the attribute of thought, now under the attribute of extension. The idea of the mind and the mind itself are therefore one and the same thing, both conceived under the one attribute of thought. The idea of the mind and the mind itself, I say, are in God by the same necessity, following from the same power of thinking.
Strictly speaking, the idea of the mind, that is, the idea of an idea, is nothing but the form of the idea insofar as the idea is considered as a mode of thinking without reference to its object. For as soon as someone knows something, they thereby know that they know it, and at the same time know that they know what they know, and so on without end. But I will discuss this further later.