Rearrange the labelled parts X, Y and Z to form the most logical sentence:\n"We have seen that, when X. think of it as losing its parts and shrivelling to a point Y. occupy any portion of space, we need not Z. we deny that a mental image can."

Introduction / Context:
This question presents a partly philosophical sentence broken into three labelled fragments X, Y, and Z. Your task is to choose the order of these fragments that produces a coherent sentence. Such questions test your understanding of logical flow, grammar, and meaning in complex sentences about abstract topics, in this case mental images and space.

Given Data / Assumptions:

• Fixed beginning: "We have seen that, when".
• X: "think of it as losing its parts and shrivelling to a point"
• Y: "occupy any portion of space, we need not"
• Z: "we deny that a mental image can"
• We must order X, Y, Z so that the full sentence is grammatical and meaningful.

Concept / Approach:
The core concepts are clause structure and logical argument. The sentence is explaining that if we make a certain denial about mental images and space, then we no longer need to think of a mental image in an odd way. The natural philosophical claim is: "We have seen that, when we deny that a mental image can occupy any portion of space, we need not think of it as losing its parts and shrivelling to a point." This structure suggests that a "when we deny that..." clause should come first, followed by "occupy any portion of space, we need not", and finally "think of it as losing its parts and shrivelling to a point".

Step-by-Step Solution:
Step 1: Identify which fragment can attach directly after "when". Both X and Z begin with a verb phrase, but Z begins with "we deny", which can naturally follow "when".Step 2: Attach Z first: "when we deny that a mental image can". This introduces a subordinate clause about what we deny.Step 3: Continue the thought with Y: "occupy any portion of space, we need not". Now we have "when we deny that a mental image can occupy any portion of space, we need not", which is grammatically sound and logically connected.Step 4: Conclude with X: "think of it as losing its parts and shrivelling to a point." Now the full sentence reads: "We have seen that, when we deny that a mental image can occupy any portion of space, we need not think of it as losing its parts and shrivelling to a point."Step 5: Compare with the options. The order we used is Z first, then Y, then X, which corresponds to option (d) ZYX.

Verification / Alternative check:
Test the other orders quickly. If we start with X, we get "when think of it as losing its parts and shrivelling to a point", which is ungrammatical because it lacks a subject before "think". If we start with Y, "when occupy any portion of space, we need not" also lacks a subject. Only Z provides a subject "we" and a complete verb phrase "we deny". Additionally, the philosophical logic is clear: first state the denial about mental images and space, then state the consequence that we no longer need to think of them as shrinking. This confirms that ZYX is the only order that produces a clear, grammatical argument.

Why Other Options Are Wrong:

• Option (a) ZXY: Produces "... when we deny that a mental image can think of it as losing its parts ..." which is nonsensical, as it treats the mental image itself as doing the thinking.
• Option (b) YZX: Begins with "when occupy any portion of space", which is missing a subject and therefore ungrammatical.
• Option (c) YXZ: Also starts improperly and leads to an incoherent structure that does not match the intended philosophical claim.

Common Pitfalls:
In reordering questions, candidates sometimes ignore subject–verb agreement and focus only on approximate meaning. This can lead to acceptance of fragments that do not form a grammatical clause after "when". Another pitfall is misplacing cause and effect; here, the denial about space is the condition, not the result, so it must appear in the "when" clause, not at the end.

Final Answer:
The correct order is ZYX, giving the sentence: "We have seen that, when we deny that a mental image can occupy any portion of space, we need not think of it as losing its parts and shrivelling to a point."