So it's got to be true. It's got to be a necessary truth.

所以它必须成立 也必须成为必然真理。

We're going to get a deep insight if it's a necessary truth about death that everyone dies alone.

如果人都将孤独死去这一说法是必然真理那它便揭示了一些深刻的内涵。

Now what makes it natural to call this principle a law of thought is that it is by thought rather than by outward observation that we persuade ourselves of its necessary truth.

现在，将这个原则称为思想法则是很自然的，因为我们是通过思想而不是通过外在观察说服自己相信它的必要真理​​。