Felicific Calculus: Formula, Morality Calculator & Example

The felicific calculus is an algorithm for calculating the degree or amount of pleasure that a specific action is likely to cause. The algorithm is also known as the utility calculus, the hedonistic calculus, and the hedonic calculus.

Here’s a work-in-progress spreadsheet to do the calculation. (Feel free to make improvements!)

Morality Calculator

Hedonic Calculus, Hedonistic Calculus: Same Bentham, Different Name

Felicific calculus, hedonic calculus, hedonistic calculus, utility calculus, and moral calculus are five names for the same seven-variable algorithm Jeremy Bentham published in An Introduction to the Principles of Morals and Legislation (1789). “Felicific” is just Latin for “happiness-making,” which philosophers prefer because “hedonistic calculus” sounds like math you’d do at a casino. Whatever you call it, the procedure is identical: score the seven variables above, sum the pleasures, subtract the pains.

Units of Pleasure and Pain

The units of measurements used in the felicific calculus are:

• Negend (aka dolor) – Unit of pain. Derived from the “negative end result”
• Posend (aka hedon) – Unit of pleasure. Derived from the “positive end result”

Variable Definitions

Variables of the pleasures and pains included in this calculation are:

1. Intensity: How strong is the pleasure?
2. Duration: How long will the pleasure last?
3. Certainty or uncertainty: How likely or unlikely is it that the pleasure will occur?
4. Propinquity or remoteness: How soon will the pleasure happen?
5. Fecundity: The probability that the action will produce other pleasures.
6. Purity: The likelihood that the action won’t cause pain.
7. Extent: How many people will be affected?

Instructions for Calculating Net Harm/Benefit of an Action

1. Consider a conscious being most immediately to be affected by an action. Rate the following for this being on a scale of 1 to 10:
   • each different pleasure that appears to be produced by it in the first instance
   • each pain that seems to be produced by it in the first instance
   • each pleasure that appears to be produced after the first. The sum constitutes the fecundity of the first pleasure and the impurity of the first pain.
   • each pain produced by it after the first. The sum constitutes the fecundity of the first pain and the impurity of the first pleasure.
2. Repeat the process for each conscious being impacted.
3. Sum the posends for everyone and subtract the negends for everyone.
4. The act is a net good for the community if the total exceeds 0 (i.e., posends exceeded negends). It’s a net evil if the result is below 0.

Worked Example: Eating Your Roommate’s Leftover Pizza

• Your pleasure: cold pizza at 2 a.m., intensity 8, certain and immediate — +8 posends
• Your impurity: guilt, plus a passive-aggressive sticky note tomorrow — −3 negends
• Roommate’s pain: discovering the empty box (7), plus eroded trust breeding future pains (2) — −9 negends
• Net total: 8 − 12 = −4 hedons. Verdict: net evil. Buy your own pizza.

References

1. Ethical calculus
2. Science of morality
3. Jeremy Bentham, An Introduction to the Principles of Morals and Legislation, London, 1789, chap. 4
4. Spreadsheet Calculator (Feel free to make improvements!)