we examine each of the eight combinations as regards each premise; (γ) and (δ) are contradicted by (1), and (β) and (ζ) by (2), so that there remain only
| ABC | (α) |
| aBC | (ε) |
| abC | (η) |
| abc. | (θ) |
To describe any term under the conditions of the premises (1) and (2), we have simply to draw out the proper combinations from this list; thus, A is represented only by ABC, that is to say
| A | = ABC, | |
| similarly | c | = abc. |
For B we have two alternatives thus stated,
B = ABC ꖌ aBC;
and for b we have
b = abC ꖌ abc.
When we have a problem involving four distinct terms we need to double the number of combinations, and as we add each new term the combinations become twice as numerous. Thus
| A, B | produce | four combinations | |
| A, B, C, | " | eight | " |
| A, B, C, D | " | sixteen | " |
| A, B, C, D, E | " | thirty-two | " |
| A, B, C, D, E, F | " | sixty-four | " |