The Holding Hands Principle is an aid to good reasoning, helping us make arguments more explicit and rigorous. Like its sister the Rabbit Principle, Holding Hands is a simple idea, yet profound and very useful.

The basic idea is that in a simple argument (a reason or objection), premises should ‘hold hands’ with each other and the contention by overlapping in the terms they contain. More formally,

    Every significant term or phrase appearing in a premise of a simple

    argument should also appear in either the contention or one of the

    other premises.

Figure 2.14

For example, consider the VitaChaff argument above. Note that the first premise contains the following significant terms or phrases:

  - VitaChaff

  - contains

  - wheat germ

‘VitaChaff ’ appears in the contention, and so the first premise ‘holds hands’ with the contention. Similarly, ‘wheat germ’ appears in the second premise, and so the premises hold hands with each other.

Figure 2.15

However, the Holding Hands Principle is not fully satisfied, since ‘contains’ does not appear elsewhere. The argument must be modified somewhere to remove the violation. One approach is illustrated above. Now, every significant term or phrase appearing anywhere in the premises appears somewhere else too.

Observing the Holding Hands Principle in this case has a number of effects:

  - It has helped ensure that no significant term or phrase is not properly bound in the overall structure of reasoning.

  - It has strengthened the connection between claims, by increasing the degree to which they have terms or phrases in common.

  - It has forced the unstated assumption VitaChaff is food into the open. (This may sound trivial, but VitaChaff might have been, say, horse feed.)

Such benefits are the reward which commonly flows from the painstaking work involved in ensuring that the Holding Hands Principle is fully satisfied.

Strategies for Removing Violations

When refining an argument to remove violations of the Holding Hands and Rabbit Principles, the following strategies can be applied:

  - Use exactly the same term or phrase for a concept, wherever it appears.

  - Strip out terms or phrases which, on reflection, are not crucial to the argument, and can be dispensed with.

  - Add another co-premise if necessary, but be very careful that in doing so you do not introduce additional Holding Hands problems.