Spinoza’s three rules of living

1. To speak in a manner intelligible to the multitude, and to comply with every general custom that does not hinder the attainment of our purpose. For we can gain from the multitude no small advantages, provided that we strive to accommodate ourselves to its understanding as far as possible: moreover, we shall in this way gain a friendly audience for the reception of the truth.

2. To indulge ourselves with pleasures only in so far as they are necessary for preserving health.

3. Lastly, to endeavor to obtain only sufficient money or other commodities to enable us to preserve our life and health, and to follow such general customs as are consistent with our purpose.

—Baruch Spinoza, De emendatione